Soup Posted at 2024-10-03 02:24:49(10Wks ago) Report Permalink URL | ||
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| Investigating the statistical likelihood of triple star systems hosting exoplanets by Universe Today  Example of a triple star system. Credit: Caltech/R. Hurt (Infrared Processing and Analysis Center, or IPAC Why is it important to search for exoplanets in triple star systems and how many can we find there? This is what a recent study accepted by Astrophysics & Space Science hopes to address after a pair of researchers from the University of Texas at Arlington investigated the statistical likelihood of triple star systems hosting exoplanets. This study holds the potential to help researchers better understand the formation and evolution of triple star systems and whether they are suitable for hosting life as we know it. The research is published on the arXiv preprint server. Here, Universe Today discusses this incredible research with Dr. Manfred Cuntz, who is a physics professor at the University of Texas at Arlington and lead author of the study, regarding the motivation behind the study, the most significant results, the importance of studying triple star systems, and the likelihood of finding exolife in triple star systems. What was the motivation behind the study? Dr. Cuntz tells Universe Today, "Ages and metallicity (i.e., the amount of heavy elements = elements other than hydrogen and helium) are fundamental properties of stars, a statement that applies to all stars. Considering that most stars (excluding the sun) are members of higher order systems, the study of stars in triple stellar systems is a natural extension of research focusing on single stars." For the study, the researchers conducted a statistical analysis regarding both the ages and metallicities of triple star systems with a total of 27 confirmed exoplanets based on past research, with the number of exoplanets in each system ranging from 1 to 5. The ages of the triple star system, with margins of error, ranged between 20 million years old to 7.2 billion years old. For context, our sun is estimated to be slightly more than 4.6 billion years old. The metallicities of the star systems, with margins of error, ranged between -0.59 and +0.56, which is often calculated based on the ratio of iron to hydrogen (Fe/H), and is also calculated with the equation X + Y + Z =1, with X being the fraction of hydrogen, Y being the fraction of helium, and Z being everything else (i.e., carbon, oxygen, silicon, iron, etc.). These values range between -4.5 and +1.0, with stars exhibiting 0, -1, greater than 0, and less than 0, indicating a star is equal in iron abundance to our sun, one-tenth the iron abundance of our sun, greater metal content than our sun, and less metal content than our sun, respectively. What were the most significant results from this study? "Two highly significant results have been identified," Dr. Cuntz tells Universe Today. "First, stars in triple stellar systems are on average notably younger than stars situated in the solar neighborhood. The most plausible explanation is a possible double selection effect due to the relatively high mass of planet-hosting stars of those systems (which spend less time on the main-sequence than low-mass stars) and that planets in triple stellar systems may be long-term orbitally unstable. "The stellar metallicities of those stars are on average solar-like; however, owing to the limited amount of data, this result is not inconsistent with the previous finding that stars with planets tend to be metal-rich, as the deduced metallicity distribution is relatively broad." The distances to the respective triple star systems range between 4.3 and 1,870 light-years from Earth, but only 6 of the 27 triple star systems reside within 100 light-years away. These six triple star systems include Alpha Centauri (4.3 light-years), Epsilon Indi (11.9 light-years), LTT 1445 (22.4 light-years), Gliese 667 (23.6 light-years), 94 Ceti (73.6 light-years), and Psi1 Draconis (74.5 light-years), with the number of total exoplanets (with exoplanet candidates indicated in parentheses) within each system being 3 (2), 1, 1, 2 (1), 1, and 1, respectively. For context, as of September 2024, the total number of confirmed exoplanetary systems within our cosmos is more than 4,300, which encompasses almost 5,800 exoplanets. Despite the small number of triple star systems that host exoplanets, what is the importance of studying triple star systems? Dr. Cuntz tells Universe Today, "Most stars (excluding the sun) are members of higher order systems, especially binaries—and in less common cases, triple stellar systems, and systems of even higher order. "Therefore, the study of planets hosted by triple stellar systems is a natural extension of the standard approach focusing on planets around single stars. The current study focuses on some of the properties of stars in triple stellar systems, which are also known to host (a) planet(s)—a relatively rare setting. The importance of the current study is to expand our general understanding of star-planet systems." For Alpha Centauri, the exoplanet Proxima Centauri b, has been confirmed to be terrestrial (rocky), approximately the size of Earth in both radius and mass, and orbiting within the habitable zone (HZ) of Proxima Centauri, one of the stars that comprise the Alpha Centauri triple star system. The only other terrestrial exoplanet orbiting within its star's HZ is Gliese 667 Cc, whose mass and radius is larger than Earth, designating it as a super-Earth. Given the small number of triple star systems that have exoplanets and even fewer that host terrestrial exoplanets orbiting in their HZ, what is the likelihood of finding exolife in triple star systems? "The only planet where we know for sure that life does exist is Earth," Dr. Cuntz tells Universe Today. "However, through both observational and theoretical studies during many decades of committed work, scientists are convinced that exolife is almost certainly real. This statement should also apply to planets in triple star systems. "However, those planets are typically subject to relatively variable environmental forcings (e.g., variable amounts of radiation received by the stellar components), which is expected to reduce the likelihood of advanced life forms, but should still permit microbial life, especially extremophiles." As the number of confirmed exoplanets continues to grow, so should the confirmed number of triple star systems that host exoplanets. When science fiction fans read about multi-star systems, they almost immediately think of the iconic scene in "Star Wars: A New Hope," in which Luke Skywalker watches two stars setting on the horizon. While Tatooine was habitable for humans and other interesting life forms, this might not be the case in the real world, as demonstrated by Proxima Centauri b currently being the only Earth-like exoplanet orbiting in its HZ within 100 light-years from Earth. Therefore, what constraints should scientists put on finding life in triple star systems? Should we instead study their moons, as the film "Avatar" depicted the semi-habitable moon Pandora orbiting a much larger exoplanet within the Alpha Centauri system? Are triple star systems with exoplanets as rare as the statistics show today? "The search for life outside of planet Earth continues to be a fascinating topic," Dr. Cuntz tells Universe Today. "Political and societal support for ongoing and future space missions is highly appreciated. We, as scientists, are grateful for the ongoing support by taxpayers around the world, but especially here in the U.S." | |
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| MafketelPosted at 2024-10-03 08:21:04(10Wks ago) Report Permalink URL | ||
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| The Red Dwarf If you come across it be careful.. Its steaming hot and sticky..  the red dwarf | |
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| Ange1Posted at 2024-10-03 08:32:23(10Wks ago) Report Permalink URL | ||
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| omg luv it   | |
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| Jase1Posted at 2024-10-06 18:13:43(10Wks ago) Report Permalink URL | ||
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|  This NASA/ESA Hubble Space Telescope image features the spiral galaxy IC 4709 located around 240 million light-years away in the southern constellation Telescopium. Hubble beautifully captures its faint halo and swirling disk filled with stars and dust bands. The compact region at its core might be the most remarkable sight. It holds an active galactic nucleus (AGN). If IC 4709’s core just held stars, it wouldn’t be nearly as bright. Instead, it hosts a gargantuan black hole, 65 million times more massive than our Sun. A disk of gas spirals around and eventually into this black hole, crashing together and heating up as it spins. It reaches such high temperatures that it emits vast quantities of electromagnetic radiation, from infrared to visible to ultraviolet light and X-rays. A lane of dark dust, just visible at the center of the galaxy in the image above, obscures the AGN in IC 4709. The dust lane blocks any visible light emission from the nucleus itself. Hubble’s spectacular resolution, however, gives astronomers a detailed view of the interaction between the quite small AGN and its host galaxy. This is essential to understanding supermassive black holes in galaxies much more distant than IC 4709, where resolving such fine details is not possible. This image incorporates data from two Hubble surveys of nearby AGNs originally identified by NASA’s Swift telescope. There are plans for Swift to collect new data on these galaxies. Swift houses three multiwavelength telescopes, collecting data in visible, ultraviolet, X-ray, and gamma-ray light. Its X-ray component will allow SWIFT to directly see the X-rays from IC 4709’s AGN breaking through the obscuring dust. ESA’s Euclid telescope — currently surveying the dark universe in optical and infrared light — will also image IC 4709 and other local AGNs. Their data, along with Hubble’s, provides astronomers with complementary views across the electromagnetic spectrum. Such views are key to fully research and better understand black holes and their influence on their host galaxies. | |
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| SoupPosted at 2024-10-08 00:30:58(10Wks ago) Report Permalink URL | ||
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| Astronomers use Webb to probe a 'steam world' in the constellation Pisces by University of Montreal  The study found that the planet’s atmosphere contains a high concentration of heavier molecules, including a significant amount of water vapor. Credit: NASA, ESA, Leah Hustak (STSCI), Ralf Crawford (STSCI) A Canadian-led international study has revealed new insights into the atmosphere of GJ 9827 d—an exoplanet orbiting the star GJ 9827 in the constellation Pisces, about 98 light-years from Earth—using the James Webb Space Telescope (JWST). The study found that the planet's atmosphere contains a high concentration of heavier molecules, including a significant amount of water vapor, making astronomers think it could very well be a "steam world." Published in The Astrophysical Journal Letters, the study was led by Caroline Piaulet-Ghorayeb, a Ph.D. candidate at Université de Montréal's Trottier Institute for Research on Exoplanets (IREx), in collaboration with researchers worldwide. Earlier this year, using Hubble Space Telescope (HST) data, IREx researchers announced they'd detected water in the atmosphere of GJ 9827 d, making it, at roughly two times the size of the Earth, the smallest exoplanet with a confirmed atmosphere. Together, these significant findings open new avenues for the search for life beyond our solar system and enhance our understanding of planetary formation and composition. An elusive goal—until now For years, scientists have focused on the detection of atmospheres on large gas giants and mini-Neptunes—planets much larger than Earth and with atmospheres dominated by hydrogen, like Jupiter and Neptune in our solar system. But until now, detecting atmospheres around smaller planets, closer to Earth-sized, has remained an elusive goal. For now, all the planets we've detected that have atmospheres are giant planets, or at best mini-Neptunes," said Piaulet-Ghorayeb, the study's lead author. "These planets have atmospheres made up mostly of hydrogen, making them more similar to gas giants in the solar system than to terrestrial planets like Earth, which have atmospheres dominated by heavier elements." Rich in heavier molecules What sets GJ 9827 d apart is its atmosphere's composition. By combining JWST/NIRISS and HST data, Piaulet-Ghorayeb showed that, unlike the hydrogen-dominated atmospheres of larger planets, GJ 9827 d's is rich in heavier molecules, with quite a bit of water vapor. This discovery marks the first robust detection of an exoplanet atmosphere where hydrogen is not the dominant component, suggesting instead a heavier, water-rich atmosphere. "It's closer in molecular weight to the carbon dioxide or nitrogen-rich atmospheres that we are currently looking for on smaller rocky planets, where we would eventually look for life," said Piaulet-Ghorayeb. She and her team made their observations via the Canadian instrument on JWST, the Near-Infrared Imager and Slitless Spectrograph (NIRISS). Using transmission spectroscopy, they analyzed the starlight passing through the planet's atmosphere as it transited (passed in front of) its host star, GJ 9827. They then combined the new JWST observations with previous HST observations to confidently show that the observed spectral features are caused by the planet's atmosphere and not by contamination from the system's star. With the data from JWST/NIRISS SOSS, scientists can finally distinguish between two types of atmospheres for the planet: one is cloudy with few heavier elements, mainly hydrogen with water only present in trace amounts; the other has a high density with many heavier elements and a lot of water. Because GJ 9827 d is close to its star, its atmosphere is likely a mix of gas and a superheated, dense state, rather than having distinct layers or clouds. Not thought to be inhabitable While GJ 9827 d itself is not thought to be habitable due to its proximity to its host star and resulting high surface temperatures (around 350°C), the discovery is a major leap forward in the search for habitable environments. The presence of a heavy, water-rich atmosphere on a small planet like GJ 9827 d provides a proof of concept that such atmospheres exist and can be studied with the JWST's precision. And that makes the prospect of finding habitable, Earth-like planets more plausible, eventually. "This is a huge step towards the goal of searching for atmospheres around smaller, terrestrial-like planets," said Piaulet-Ghorayeb. "GJ 9827 d is the first planet where we detect an atmosphere rich in heavy molecules, just like the terrestrial planets of the solar system, and the first confirmed example in a long time of a 'steam world' posited by the scientific community." Such "steam worlds" are thought to have thick, water-rich atmospheres without surface ice or liquid water, instead maintaining steam atmospheres due to their proximity to their host stars. They're like the icy moons Europa and Ganymede, only close enough to their stars that water appears as steam in the atmosphere, not under an ice layer. Further planned JWST observations of GJ 9827 d in the coming months could shed more light on the components of its steam atmosphere, the astronomers hope. | |
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| Jase1Posted at 2024-10-09 12:51:47(9Wks ago) Report Permalink URL | ||
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| This Ancient "Rebel" Galaxy Closely Mirroring the Milky Way Has Astronomers Freaked Out  Astronomers peering into some of the furthest reaches of our universe have made a "baffling" discovery: the most distant rotating disc galaxy ever observed. And it closely — if not eerily — resembles our own. The structure dubbed REBELS-25 was revealed in high detail using the Atacama Large Millimeter/submillimeter Array (ALMA), as detailed in a study accepted for publication in the journal Monthly Notices of the Royal Astronomical Society. What really caught the researchers off guard was the galaxy's unusually smooth and tidy structure, something that scientists have suggested takes billions of years worth of evolutionary change. "According to our understanding of galaxy formation, we expect most early galaxies to be small and messy looking," said coauthor and Leiden University astronomer Jacqueline Hodge in a statement. REBELS-25 stands out as it (and its smooth resemblance to the Milky Way) dates back to when the Universe was a nascent 700 million years old, just five percent of its current age (13.7 billion years old). This is despite REBELS-25’s uncanny resemblance to the Milky Way, which is just slightly younger than the universe (at 13.6 billion years old). In other words, we thought it took 13.6 billion years to look as smooth as us, when in fact, as REBELS-25 may indeed prove, it only takes 700 million years. "Seeing a galaxy with such similarities to our own Milky Way, that is strongly rotation-dominated, challenges our understanding of how quickly galaxies in the early Universe evolve into the orderly galaxies of today's cosmos," explained first author and Leiden University doctoral student Lucie Rowland. Spiraling Arms Thanks to ALMA's extremely high resolution, astronomers could make out REBELS-25's unusually ordered structure and motion. The evidence also suggests the galaxy has spiral arms and an elongated central bar, much like the Milky Way. "Finding further evidence of more evolved structures would be an exciting discovery, as it would be the most distant galaxy with such structures observed to date," said Rowland. The team is now hoping to get an even closer look, possibly with the help of NASA's James Webb Space Telescope, which could further undermine our current understanding of how galaxies evolve over billions of years. "In particular, ongoing ALMA observations of other REBELS galaxies will enable robust kinematic modeling of additional rotating disc candidates," the researchers wrote in their paper. | |
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| SoupPosted at 2024-10-09 21:30:46(9Wks ago) Report Permalink URL | ||
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| Astronomers discover dozens of massive stars launched from young star cluster R136 by Leiden University  Artistic impression of star cluster R136 containing hundreds of thousands of stars in a huge star-forming region in the Large Magellanic Cloud. In two bursts in the last two million years, 55 massive stars have been ejected at speeds above 100,000 km/hr. This is an artistic impression; the runaway stars are actually like the white dots seen all over the field. Data from GAIA is needed to determine which stars are launched from the cluster. Credit: Danielle Futselaar, James Webb Space Telescope/NIRCam - NASA, ESA, CSA and STScI. Astronomers have used data from the European Gaia Space Telescope to discover 55 high-speed stars launched from the young star cluster R136 in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. This increases tenfold the number of known "runaway stars" in this region. The team of astronomers, including Simon Portegies Zwart of Leiden Observatory, published their results this week in Nature. When star clusters form, near collisions of the closely packed and crisscross moving newborn stars may result in the ejection of stars out of the young cluster. The astronomers, led by UvA Ph.D. student Mitchel Stoop, found that the young cluster R136 has launched as many as a third of its most massive stars in the last few million years, at speeds above 100,000 km/hr. Those stars travel up to 1,000 light years from their birthplace before exploding as supernovas at their end of life, producing a neutron star or black hole. But Stoop and his colleagues made another surprising discovery: there was not a single period when the stars were dynamically ejected, but two. Stoop explains, "The first episode was 1.8 million years ago, when the cluster formed, and fits with the ejection of stars during the formation of the cluster. The second episode was only 200,000 years ago and had very different characteristics. For example, the runaway stars of this second episode move more slowly and are not shot away in random directions as in the first episode, but in a preferred direction." "We think that the second episode of shooting away stars was due to the interaction of R136 with another nearby cluster (that was only discovered in 2012). The second episode may foretell that the two clusters will mix and merge in the near future," says co-author Alex de Koter (UvA). Massive stars eventually explode as supernovas. During their lifetime, they are extremely bright—up to more than a million times brighter than the sun—and emit mainly ultraviolet light that ionizes the surrounding hydrogen gas. They live for only a short time (millions of years) and normally still explode in the star-forming region in which they were born. Such a star-forming region consists of clouds of gas and dust that dampen the effect that massive stars have on their surroundings.  On-sky distribution of runaways from R136 in the last 3 Myr. Credit: Nature (2024). DOI: 10.1038/s41586-024-08013-8 This is the first time such a huge number (55) of high-speed stars originating from a single cluster have been found. R136 is a very special cluster, with hundreds of thousands of stars including the most massive stars known (up to 300 times the mass of the sun). It is part—and the "prima donna"—of the largest star-forming region we know of within a radius of five million light years. "Now that we have discovered that a third of the massive stars are ejected from their birth regions early in their lives—and that they exert their influence beyond those regions—the impact of massive stars on the structure and evolution of galaxies is probably much larger than previously thought. It is even possible that runaway stars formed in the early universe made an important contribution to the so-called re-ionization of the universe caused by ultraviolet light," says co-author Lex Kaper (UvA). The astronomers used data from ESA's Gaia telescope, which measures the positions, distances and velocities of more than a billion stars. Gaia is located far beyond the moon at a distance of 1.5 million kilometers from Earth. The team's main goal was to test the limits of Gaia's capabilities. R136 is located in the Large Magellanic Cloud, a sister galaxy to the Milky Way, at a distance of 160,000 light-years. That's extremely far for Gaia measurements. "R136 has only just formed (1.8 million years ago) and so the runaway stars could not yet be so far away that it becomes impossible to identify them. If you can find a lot of those stars, you can make reliable statistical statements. This worked out beyond expectations, and we are tremendously pleased with the results. Discovering something new is always a thrill for a scientist," De Koter concludes. Incidentally, during his doctoral research (1946), Dutch astronomer Adriaan Blaauw (April 12, 1914—December 1, 2010) found the first indications of the existence of runaway stars, stars moving at high speed through the Milky Way galaxy. With data from first the ESA space mission Hipparcos, which Blaauw co-lead, and now Gaia, star clusters and the motions of runaway stars can be studied in detail. | |
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| Jase1Posted at 2024-10-13 17:26:14(9Wks ago) Report Permalink URL | ||
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|  Imagine a sky full of hundreds of stars as bright as the full moon… If our solar system were a part of this “super star” cluster, that is what we might experience. Here is Webb’s look at Westerlund 1, one of the closest clusters of its kind. Super star clusters are young and contain more than 10,000 times the mass of the Sun packed into a small volume. Westerlund 1 is the most massive yet identified in our galaxy, with 50,000 to 100,000 times the mass of the Sun contained within a region less than six light-years across. Still considered an open cluster now, someday it will evolve into a globular cluster - a roughly spherical, tightly packed collection of old stars bound together by gravity. Super star clusters are one of the most extreme environments in which stars and planets can form. Because our galaxy is past its peak of star formation, and because stars live relatively short lives, only a few of these clusters still exist to give us clues to that past era. Westerlund 1 has a large, dense, and diverse population of evolved, massive stars. It contains so many massive stars that in a timespan of less than 40 million years, it’ll be the site of more than 1500 supernovas. This cluster is a natural laboratory for the study of extreme stellar physics, helping us learn how the most massive stars in our galaxy live and die, and how stellar winds, supernovae, and other ejected material affect star formation within their environment. Image description: A dense cluster of bright stars, each with six large and two small diffraction spikes, due to the telescope’s optics. They have a variety of sizes depending on their brightness and distance from us in the cluster, and different colors reflecting different types of star. Patches of billowing red gas can be seen in and around the cluster, lit up by the stars. Small stars in the cluster blend into a background of distant stars and galaxies on black. Image credit: ESA/Webb, NASA & CSA, M. Zamani (ESA/Webb), M. G. Guarcello (INAF-OAPA) and the EWOCS team | |
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| Jase1Posted at 2024-10-14 18:31:47(9Wks ago) Report Permalink URL | ||
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|  This side-by-side comparison shows observations of the Southern Ring Nebula in near-infrared light, at left, and mid-infrared light, at right, from NASA’s Webb Telescope. This scene was created by a white dwarf star – the remains of a star like our Sun after it shed its outer layers and stopped burning fuel through nuclear fusion. Those outer layers now form the ejected shells all along this view. In the Near-Infrared Camera (NIRCam) image, the white dwarf appears to the lower left of the bright, central star, partially hidden by a diffraction spike. The same star appears – but brighter, larger, and redder – in the Mid-Infrared Instrument (MIRI) image. This white dwarf star is cloaked in thick layers of dust, which make it appear larger. The brighter star in both images hasn’t yet shed its layers. It closely orbits the dimmer white dwarf, helping to distribute what it’s ejected. Over thousands of years and before it became a white dwarf, the star periodically ejected mass – the visible shells of material. As if on repeat, it contracted, heated up – and then, unable to push out more material, pulsated. Stellar material was sent in all directions – like a rotating sprinkler – and provided the ingredients for this asymmetrical landscape. Today, the white dwarf is heating up the gas in the inner regions – which appear blue at left and red at right. Both stars are lighting up the outer regions, shown in orange and blue, respectively. The images look very different because NIRCam and MIRI collect different wavelengths of light. NIRCam observes near-infrared light, which is closer to the visible wavelengths our eyes detect. MIRI goes farther into the infrared, picking up mid-infrared wavelengths. The second star appears more clearly in the MIRI image, because this instrument can see the gleaming dust around it. The stars – and their layers of light – steal more attention in the NIRCam image, while dust plays the lead in the MIRI image, specifically dust that is illuminated. Peer at the circular region at the center of both images. Each contains a wobbly, asymmetrical belt of material. This is where two “bowls” that make up the nebula meet. (In this view, the nebula is at a 40-degree angle.) This belt is easier to spot in the MIRI image – look for the yellowish circle – but is also visible in the NIRCam image. The light that travels through the orange dust in the NIRCam image – which looks like spotlights – disappears at longer infrared wavelengths in the MIRI image. In near-infrared light, stars have more prominent diffraction spikes because they are so bright at these wavelengths. In mid-infrared light, diffraction spikes also appear around stars, but they are fainter and smaller (zoom in to spot them). Physics is the reason for the difference in the resolution of these images. NIRCam delivers high-resolution imaging because these wavelengths of light are shorter. MIRI supplies medium-resolution imagery because its wavelengths are longer – the longer the wavelength, the coarser the images are. But both deliver an incredible amount of detail about every object they observe – providing never-before-seen vistas of the universe. | |
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| SoupPosted at 2024-10-14 19:57:45(9Wks ago) Report Permalink URL | ||
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| 'Killer electrons': Lightning storms play cosmic pinball with space weather by Daniel Strain, University of Colorado at Boulder  Visualization showing how magnetic field lines, thin cyan lines, circling Earth can trap charged particles, thin yellow lines. Credit: UCLA EPSS/NASA SVS When lightning strikes, the electrons come pouring down. In a new study, researchers at the University of Colorado Boulder, led by an undergraduate student, have discovered a novel connection between weather on Earth and space weather. The team utilized satellite data to reveal that lightning storms on our planet can dislodge particularly high-energy, or "extra-hot," electrons from the inner radiation belt—a region of space enveloped by charged particles that surround Earth like an inner tube. The team's results could help satellites and even astronauts avoid dangerous radiation in space. This is one kind of downpour you don't want to get caught in, said lead author and undergraduate Max Feinland. "These particles are the scary ones or what some people call 'killer electrons,'" said Feinland, who received his bachelor's degree in aerospace engineering sciences at CU Boulder in spring 2024. "They can penetrate metal on satellites, hit circuit boards and can be carcinogenic if they hit a person in space." The study appeared Oct.8 in the journal Nature Communications. The findings cast an eye toward the radiation belts, which are generated by Earth's magnetic field. Lauren Blum, a co-author of the paper and assistant professor in the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder, explained that two of these regions encircle our planet: While they move a lot over time, the inner belt tends to begin more than 600 miles above the surface. The outer belt starts roughly around 12,000 miles from Earth. These pool floaties in space trap charged particles streaming toward our planet from the sun, forming a sort of barrier between Earth's atmosphere and the rest of the solar system. But they're not exactly airtight. Scientists, for example, have long known that high-energy electrons can fall toward Earth from the outer radiation belt. Blum and her colleagues, however, are the first to spot a similar rain coming from the inner belt. Earth and space, in other words, may not be as separate as they look. "Space weather is really driven both from above and below," Blum said. Bolt from the blue It's a testament to the power of lightning. When a lightning bolt flashes in the sky on Earth, that burst of energy may also send radio waves spiraling deep into space. If those waves smack into electrons in the radiation belts, they can jostle them free—a bit like shaking your umbrella to knock the water off. In some cases, such "lightning-induced electron precipitation" can even influence the chemistry of Earth's atmosphere. To date, researchers had only collected direct measurements of lower energy, or "colder," electrons falling from the inner radiation belt. "Typically, the inner belt is thought to be kind of boring," Blum said. "It's stable. It's always there."  Visualization of the radiation belts surrounding Earth. Credit: NASA Her team's new discovery came about almost by accident. Feinland was analyzing data from NASA's now-decommissioned Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite when he saw something odd: clumps of what seemed to be high-energy electrons moving through the inner belt. "I showed Lauren some of my events, and she said, 'That's not where these are supposed to be,'" Feinland said. "Some literature suggests that there aren't any high-energy electrons in the inner belt at all." The team decided to dig deeper. In all, Feinland counted 45 surges of high-energy electrons in the inner belt from 1996 to 2006. He compared those events to records of lightning strikes in North America. Sure enough, some of the spikes in electrons seemed to happen less than a second after lightning strikes on the ground. Electron pinball Here's what the team thinks is happening: Following a lightning strike, radio waves from Earth kick off a kind of manic pinball game in space. They knock into electrons in the inner belt, which then begin to bounce between Earth's northern and southern hemispheres—going back and forth in just 0.2 seconds. And each time the electrons bounce, some of them fall out of the belt and into our atmosphere. "You have a big blob of electrons that bounces, and then returns and bounces again," Blum said. "You'll see this initial signal, and it will decay away." Blum isn't sure how often such events happen. They may occur mostly during periods of high solar activity when the sun spits out a lot of high-energy electrons, stocking the inner belt with these particles. The researchers want to understand these events better so that they can predict when they may be likely to occur, potentially helping to keep people and electronics in orbit safe. Feinland, for his part, is grateful for the chance to study these magnificent storms. "I didn't even realize how much I liked research until I got to do this project," he said. Other co-authors of the new study included Robert Marshall, associate professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences at CU Boulder, Longzhi Gan of Boston University, Mykhaylo Shumko of the Johns Hopkins University Applied Physics Laboratory and Mark Looper of The Aerospace Corporation. | |
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| Jase1Posted at 2024-10-15 11:51:10(9Wks ago) Report Permalink URL | ||
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|  NASA astronaut Matthew Dominick captured this timelapse photo of Comet C/2023 A3 (Tsuchinshan-ATLAS) from the International Space Station as it orbited 272 miles above the South Pacific Ocean southeast of New Zealand just before sunrise on Sept. 28, 2024. At the time, the comet was about 44 million miles away from Earth. Though the comet is very old, it was just discovered in 2023, when it approached the inner solar system on its highly elliptical orbit for the first time in documented human history. Beginning in mid-October 2024, Comet C/2023 A3 (Tsuchinshan-ATLAS) will become visible low in the west following sunset. If the comet’s tail is well-illuminated by sunlight, it could be visible to the unaided eye. Oct. 14-24 is the best time to observe, using binoculars or a small telescope. The comet hails from the Oort Cloud, which scientists think is a giant spherical shell surrounding our solar system. It is like a big, thick-walled bubble made of icy pieces of space debris the sizes of mountains and sometimes larger. The Oort Cloud lies far beyond Pluto and the most distant edges of the Kuiper Belt and may contain billions, or even trillions, of objects. | |
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| SoupPosted at 2024-10-15 23:52:09(9Wks ago) Report Permalink URL | ||
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| Revealing the hidden universe with full-shell X-ray optics by NASA  A composite X-ray/Optical/Infrared image of the Crab Pulsar. The X-ray image from the Chandra X-ray Observatory (blue and white), reveals exquisite details in the central ring structures and gas flowing out of the polar jets. Optical light from the Hubble Space Telescope (purple) shows foreground and background stars as pinpoints of light. Infrared light from the Spitzer Space Telescope (pink) traces cooler gas in the nebula. Finally, magnetic field direction derived from X-ray polarization observed by the Imaging X-ray Polarimetry Explorer is shown as orange lines. Credit: Magnetic field lines: NASA/Bucciantini et al; X-ray: NASA/CXC/SAO; Optical: NASA/STScI; Infrared: NASA-JPL-Caltech The study of X-ray emission from astronomical objects reveals secrets about the universe at the largest and smallest spatial scales. Celestial X-rays are produced by black holes consuming nearby stars, emitted by the million-degree gas that traces the structure between galaxies, and can be used to predict whether stars may be able to host planets hospitable to life. X-ray observations have shown that most of the visible matter in the universe exists as hot gas between galaxies and have conclusively demonstrated that the presence of "dark matter" is needed to explain galaxy cluster dynamics, that dark matter dominates the mass of galaxy clusters, and that it governs the expansion of the cosmos. X-ray observations also enable us to probe the mysteries of the universe on the smallest scales. X-ray observations of compact objects such as white dwarfs, neutron stars, and black holes allow us to use the universe as a physics laboratory to study conditions that are orders of magnitude more extreme in terms of density, pressure, temperature, and magnetic field strength than anything that can be produced on Earth. In this astrophysical laboratory, researchers expect to reveal new physics at the subatomic scale by conducting investigations such as probing the neutron star equation of state and testing quantum electrodynamics with observations of neutron star atmospheres. At NASA's Marshall Space Flight Center, a team of scientists and engineers is building, testing, and flying innovative optics that bring the universe's X-ray mysteries into sharper focus. Unlike optical telescopes that create images by reflecting or refracting light at near-90-degree angles (normal incidence), focusing X-ray optics must be designed to reflect light at very small angles (grazing incidence). At normal incidence, X-rays are either absorbed by the surface of a mirror or penetrate it entirely. However, at grazing angles of incidence, X-rays reflect very efficiently due to an effect called total external reflection. In grazing incidence, X-rays reflect off the surface of a mirror like rocks skipping on the surface of a pond. A classic design for astronomical grazing incidence optics is the Wolter-I prescription, which consists of two reflecting surfaces, a parabola and a hyperbola. This optical prescription is revolved around the optical axis to produce a full-shell mirror (i.e., the mirror spans the full circumference) that resembles a gently tapered cone. To increase the light collecting area, multiple mirror shells with incrementally larger diameters and a common focus are fabricated and nested concentrically to comprise a mirror module assembly (MMA). Focusing optics are critical to studying the X-ray universe, because in contrast to other optical systems like collimators or coded masks, they produce high signal-to-noise images with low background noise. Two key metrics that characterize the performance of X-ray optics are angular resolution, which is the ability of an optical system to discriminate between closely spaced objects, and effective area, which is the light collecting area of the telescope, typically quoted in units of cm2. Angular resolution is typically measured as the half-power diameter (HPD) of a focused spot in units of arcseconds. The HPD encircles half of the incident photons in a focused spot and measures the sharpness of the final image; a smaller number is better.  Schematic of a full-shell Wolter-I X-ray optic mirror module assembly with five concentrically nested mirror shells. Parallel rays of light enter from the left, reflect twice off the reflective inside surface of the shell (first off the parabolic segment and then off the hyperbolic segment), and converge at the focal plane. Credit: NASA MSFC NASA Marshall Space Flight Center (MSFC) has been building and flying lightweight, full-shell, focusing X-ray optics for over three decades, always meeting or exceeding angular resolution and effective area requirements. MSFC utilizes an electroformed nickel replication (ENR) technique to make these thin full-shell X-ray optics from nickel alloy. X-ray optics development at MSFC began in the early 1990s with the fabrication of optics to support NASA's Advanced X-ray Astrophysics Facility (AXAF-S) and then continued via the Constellation-X technology development programs. In 2001, MSFC launched a balloon payload that included two modules each with three mirrors, which produced the first focused hard X-ray (>10 keV) images of an astrophysical source by imaging Cygnus X-1, GRS 1915, and the Crab Nebula. This initial effort resulted in several follow-up missions over the next 12 years, and became known as the High Energy Replicated Optics (HERO) balloon program. In 2012, the first of four sounding rocket flights of the Focusing Optics X-ray Solar Imager (FOXSI) flew with MSFC optics onboard, producing the first focused images of the sun at energies greater than 5 keV. In 2019, the Astronomical Roentgen Telescope X-ray Concentrator (ART-XC) instrument on the Spectr-Roentgen-Gamma Mission, launched with seven MSFC-fabricated X-ray MMAs, each containing 28 mirror shells. ART-XC is currently mapping the sky in the 4-30 keV hard X-ray energy range, studying exotic objects like neutron stars in our own galaxy as well as active galactic nuclei, which are spread across the visible universe. In 2021, the Imaging X-ray Polarimetry Explorer (IXPE) flew and is now performing extraordinary science with an MSFC-led team using three, 24-shell MMAs that were fabricated and calibrated in-house. Most recently, in 2024, the fourth FOXSI sounding rocket campaign launched with a high-resolution MSFC MMA. The optics achieved 9.5 arcsecond HPD angular resolution during a pre-flight test with an expected 7 arcsecond HPD in gravity-free flight, making this the highest angular resolution flight observation made with a nickel-replicated X-ray optic. Currently, MSFC is fabricating an MMA for the Rocket Experiment Demonstration of a Soft X-ray (REDSoX) polarimeter, a sounding rocket mission that will fly a novel soft X-ray polarimeter instrument to observe active galactic nuclei. The REDSoX MMA optic will be 444 mm in diameter, which will make it the largest MMA ever produced by MSFC and the second largest replicated nickel X-ray optic in the world. The ultimate performance of an X-ray optic is determined by errors in the shape, position, and roughness of the optical surface. To push the performance of X-ray optics toward even higher angular resolution and achieve more ambitious science goals, MSFC is currently engaged in a fundamental research and development effort to improve all aspects of full-shell optics fabrication.  Scientists Wayne Baumgartner (left, crouched) and Nick Thomas (left, standing) calibrate an IXPE MMA in the MSFC 100 m Beamline. Scientist Stephen Bongiorno (right) applies epoxy to an IXPE shell during MMA assembly. Credit: NASA MSFC Given that these optics are made with the electroformed nickel replication technique, the fabrication process begins with creation of a replication master, called the mandrel, which is a negative of the desired optical surface. First, the mandrel is figured and polished to specification, then a thin layer of nickel alloy is electroformed onto the mandrel surface. Next, the nickel alloy layer is removed to produce a replicated optical shell, and finally, the thin shell is attached to a stiff holding structure for use. Each step in this process introduces some degree of error into the final replicated shell. Research and development efforts at MSFC are currently concentrating on reducing distortion induced during the electroforming metal deposition and release steps. Electroforming-induced distortion is caused by material stress built into the electroformed material as it deposits onto the mandrel. Decreasing release-induced distortion is a matter of reducing adhesion strength between the shell and mandrel, increasing strength of the shell material to prevent yielding, and reducing point defects in the release layer. Additionally, verifying the performance of these advanced optics requires world-class test facilities. The basic premise of testing an optic designed for X-ray astrophysics is to place a small, bright X-ray source far away from the optic. If the angular size of the source as viewed from the optic is smaller than the angular resolution of the optic, the source is effectively simulating X-ray starlight. Due to the absorption of X-rays by air, the entire test facility's light path must be placed inside a vacuum chamber. At MSFC, a group of scientists and engineers operate the Marshall 100-meter X-ray beamline, a world-class end-to-end test facility for flight and laboratory X-ray optics, instruments, and telescopes. As per the name, it consists of a 100-meter-long vacuum tube with an 8-meter-long, 3-meter-diameter instrument chamber and a variety of X-ray sources ranging from 0.25—114 keV. Across the street sits the X-Ray and Cryogenic Facility (XRCF), a 527-meter-long beamline with an 18-meter-long, 6-meter-diameter instrument chamber. These facilities are available for the scientific community to use and highlight the comprehensive optics development and test capability that Marshall is known for. Within the X-ray astrophysics community, there exists a variety of angular resolution and effective area needs for focusing optics. Given its storied history in X-ray optics, MSFC is uniquely poised to fulfill requirements for large or small, medium- or high-angular-resolution X-ray optics. To help guide technology development, the astrophysics community convenes once per decade to produce a decadal survey. The need for high-angular-resolution and high-throughput X-ray optics is strongly endorsed by the National Academies of Sciences, Engineering, and Medicine report, "Pathways to Discovery in Astronomy and Astrophysics for the 2020s". In pursuit of this goal, MSFC is continuing to advance the state of the art in full-shell optics. This work will enable the extraordinary mysteries of the X-ray universe to be revealed. | |
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| xSLYGUYxPosted at 2024-10-16 03:34:19(9Wks ago) Report Permalink URL | ||
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| Mr Musk is going to get us to Mars. | |
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| xSLYGUYxPosted at 2024-10-16 17:23:48(8Wks ago) Report Permalink URL | ||
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| Starship Team  | |
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| SoupPosted at 2024-10-16 21:19:25(8Wks ago) Report Permalink URL | ||
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| It's twins! Mystery of famed brown dwarf solved by California Institute of Technology  This artwork highlights a pair of recently uncovered brown dwarf twins, named Gliese 229Ba and Gliese 229Bb. Gliese 229B, discovered in 1995, was the first-ever confirmed brown dwarf, but until now astronomers thought they were observing a single body not two. New observations from the European Southern Observatory's Very Large Telescope in Chile revealed that the orb is two brown dwarfs tightly orbiting around each other every 12 days (as indicated by the orange and blue orbital lines), with a separation only 16 times larger than the distance between Earth and the moon. The brown dwarf pair orbit a cool M-dwarf star every 250 years. Credit: K. Miller, R. Hurt (Caltech/IPAC) Hundreds of papers have been written about the first known brown dwarf, Gliese 229B, since its discovery by Caltech researchers at the Institute's Palomar Observatory in 1995. But a pressing mystery has persisted about this orb: It is too dim for its mass. Brown dwarfs are lighter than stars, and heavier than gas giants like Jupiter. And while astronomers had measured the mass of Gliese 229B to be about 70 times that of Jupiter, an object of that heft should shine more brightly than what the telescopes had observed. Now, a Caltech-led international team of astronomers has at last solved that mystery: The brown dwarf is actually a pair of tight-knit brown dwarfs, weighing about 38 and 34 times the mass of Jupiter, that whip around each other every 12 days. The observed brightness levels of the pair match what is expected for two small, dim brown dwarfs in this mass range. "Gliese 229B was considered the poster-child brown dwarf," says Jerry W. Xuan, a graduate student working with Dimitri Mawet, the David Morrisroe Professor of Astronomy. "And now we know we were wrong all along about the nature of the object. It's not one but two. We just weren't able to probe separations this close until now." Xuan is lead author of a study reporting the findings in the journal Nature, titled "The cool brown dwarf Gliese 229B is a close binary." A separate independent study in The Astrophysical Journal Letters, led by Sam Whitebook, a Caltech graduate student, and Tim Brandt, an associate astronomer at the Space Telescope Science Institute in Baltimore, also concluded that Gliese 229B is a pair of brown dwarfs. The discovery leads to new questions about how tight-knit brown dwarf duos like this one form and suggests that similar brown dwarf binaries—or even exoplanet binaries—may be waiting to be found. (An exoplanet is a planet that orbits a star other than our sun.) "This discovery that Gliese 229B is binary not only resolves the recent tension observed between its mass and luminosity but also significantly deepens our understanding of brown dwarfs, which straddle the line between stars and giant planets," says Mawet, who is also a senior research scientist at JPL, which is managed by Caltech for NASA. Gliese 229B was discovered in 1995 by a Caltech team that included Rebecca Oppenheimer, then a Caltech graduate student; Shri Kulkarni, the George Ellery Hale Professor of Astronomy and Planetary Science; Keith Matthews, an instrument specialist at Caltech; and other colleagues. The astronomers used Palomar Observatory to discover that Gliese 229B possessed methane in its atmosphere—a phenomenon typical of gas giants like Jupiter but not of stars. The finding marked the first confirmed detection of a class of cool star-like objects called brown dwarfs—the missing link between planets and stars—that had been theorized about 30 years prior. "Seeing the first object smaller than a star orbiting another sun was exhilarating," says Oppenheimer, who is a co-author of the new study and an astrophysicist at the American Museum of Natural History. "It started a cottage industry of people seeking oddballs like it back then, but it remained an enigma for decades." Indeed, nearly 30 years after its discovery and hundreds of observations later, Gliese 229B still puzzled astronomers with its unexpected dimness. The scientists suspected Gliese 229B might be twins, but "to evade notice by astronomers for 30 years, the two brown dwarfs would have to be very close to each other," says Xuan. To resolve Gliese 229B into two objects, the team used two different instruments, both based at the European Southern Observatory's Very Large Telescope in Chile. They used the GRAVITY instrument, an interferometer that combines light from four different telescopes, to spatially resolve the body into two, and they used the CRIRES+ (CRyogenic high-resolution InfraRed Echelle Spectrograph) instrument to detect distinct spectral signatures from the two objects. The latter method involved measuring the motion (or doppler shift) of molecules in the atmosphere of the brown dwarfs, which indicated that one body was headed toward us on Earth and the other away—and vice versa as the pair orbited each other. "It is so nice to see that almost 30 years later, there has been a new development," says Kulkarni, who is not an author on the current paper. "Now this binary system stuns again." These observations, taken over five months, showed that the brown dwarf duo, now called Gliese 229Ba and Gliese 229Bb, orbit each other every 12 days with a separation only 16 times larger than the distance between Earth and the moon. Together, the pair orbit an M-dwarf star (a smaller, redder star than our sun) every 250 years. "These two worlds whipping around each other are actually smaller in radius than Jupiter. They'd look quite strange in our night sky if we had something like them in our own solar system," says Oppenheimer. "This is the most exciting and fascinating discovery in substellar astrophysics in decades." How this whirling pair of cosmic orbs came to be is still a mystery. Some theories say brown dwarf pairs could form within the swirling disks of material that encircle a forming star. The disk would fragment into two seeds of brown dwarfs, which would then become gravitationally bound after a close encounter. Whether these same formation mechanisms are at work to form pairs of planets around other stars remains to be seen. In the future, the team would like to search for even more closely orbiting brown dwarf binaries with instruments such as the Keck Planet Imager and Characterizer (KPIC), which was developed by a team led by Mawet at the W. M. Keck Observatory in Hawai'i, as well as the Keck Observatory's upcoming High-resolution Infrared SPectrograph for Exoplanet Characterization (HISPEC), which is under construction at Caltech and other laboratories by a team led by Mawet. "The fact that the first known brown dwarf companion is a binary bodes well for ongoing efforts to find more," says Xuan. | |
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| vtwin88cubePosted at 2024-10-18 15:25:40(8Wks ago) Report Permalink URL | ||||
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|  Science.Channel.Through.The.Wormhole.SE01.2010.720p.HDTV.x264 
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| Jase1Posted at 2024-10-20 17:25:44(8Wks ago) Report Permalink URL | ||
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|  This NASA/ESA Hubble Space Telescope image features the spiral galaxy IC 4709 located around 240 million light-years away in the southern constellation Telescopium. Hubble beautifully captures its faint halo and swirling disk filled with stars and dust bands. The compact region at its core might be the most remarkable sight. It holds an active galactic nucleus (AGN). If IC 4709’s core just held stars, it wouldn’t be nearly as bright. Instead, it hosts a gargantuan black hole, 65 million times more massive than our Sun. A disk of gas spirals around and eventually into this black hole, crashing together and heating up as it spins. It reaches such high temperatures that it emits vast quantities of electromagnetic radiation, from infrared to visible to ultraviolet light and X-rays. A lane of dark dust, just visible at the center of the galaxy in the image above, obscures the AGN in IC 4709. The dust lane blocks any visible light emission from the nucleus itself. Hubble’s spectacular resolution, however, gives astronomers a detailed view of the interaction between the quite small AGN and its host galaxy. This is essential to understanding supermassive black holes in galaxies much more distant than IC 4709, where resolving such fine details is not possible. This image incorporates data from two Hubble surveys of nearby AGNs originally identified by NASA’s Swift telescope. There are plans for Swift to collect new data on these galaxies. Swift houses three multiwavelength telescopes, collecting data in visible, ultraviolet, X-ray, and gamma-ray light. Its X-ray component will allow SWIFT to directly see the X-rays from IC 4709’s AGN breaking through the obscuring dust. ESA’s Euclid telescope — currently surveying the dark universe in optical and infrared light — will also image IC 4709 and other local AGNs. Their data, along with Hubble’s, provides astronomers with complementary views across the electromagnetic spectrum. Such views are key to fully research and better understand black holes and their influence on their host galaxies. | |
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| Jase1Posted at 2024-10-21 11:03:35(8Wks ago) Report Permalink URL | ||
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|  The Oort Cloud comet, called C/2023 A3 Tsuchinshan-ATLAS, passes over Southeast Louisiana near New Orleans, home of NASA’s Michoud Assembly Facility, Sunday, Oct. 13, 2024. The comet is making its first appearance in documented human history; it was last seen in the night sky 80,000 years ago. The Tsuchinshan-ATLAS comet made its first close pass by Earth in mid-October and will remain visible to viewers in the Northern Hemisphere just between the star Arcturus and planet Venus through early November. This comet comes from the Oort Cloud, far beyond Pluto and the most distant edges of the Kuiper Belt. Though Comet C/2023 A3 will be visible through early November, the best time to observe is between now and Oct. 24. | |
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| SoupPosted at 2024-10-22 00:28:01(8Wks ago) Report Permalink URL | ||
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| Betelgeuse Betelgeuse? Bright star Betelgeuse likely has a 'Betelbuddy' stellar companion by Simons Foundation  Graphical depiction of Betelgeuse and the Betelbuddy. Credit: Lucy Reading-Ikkanda/Simons Foundation One of the brightest stars in the night sky, Betelgeuse, may not be on the brink of exploding as a supernova, according to a new study of the star's brightening and dimming. Instead, recent research shows that the observed pulsing of the starlight is probably caused by an unseen companion star orbiting Betelgeuse. Formally named Alpha Ori B, the "Betelbuddy" (as astrophysicist Jared Goldberg calls it) acts like a snowplow as it orbits Betelgeuse, pushing light-blocking dust out of the way and temporarily making Betelgeuse seem brighter. Goldberg and his colleagues present their simulations of this process in a paper accepted for publication in The Astrophysical Journal. The findings are published on the arXiv preprint server. "We ruled out every intrinsic source of variability that we could think of as to why the brightening and dimming was happening in this way," says Goldberg, the study's lead author and a Flatiron research fellow at the Flatiron Institute's Center for Computational Astrophysics. "The only hypothesis that seemed to fit is that Betelgeuse has a companion." Goldberg co-authored the study with Meridith Joyce of the University of Wyoming and László Molnár of Konkoly Observatory at the HUN-REN Research Centre for Astronomy and Earth Sciences in Hungary. Uncovering the 'Betelbuddy' Betelgeuse is a red giant star around 100,000 times the brightness of our sun and more than 400 million times the volume. The star is nearing the end of its life span, and when it dies, the resulting explosion will be bright enough to see during the day for weeks. Astronomers can predict when Betelgeuse will die by effectively "checking its pulse." It's a variable star, meaning it gets brighter and dimmer, pulsing like a heartbeat. In Betelgeuse's case, there are two heartbeats: one that pulses on a timescale a little longer than a year, and one that pulses on a timescale of about six years.  Infographic describing how the Betelbuddy affects Betelgeuse's apparent brightness. Credit: Lucy Reading-Ikkanda/Simons Foundation One of these heartbeats is Betelgeuse's fundamental mode, a pattern of brightening and dimming that's intrinsic to the star itself. If the star's fundamental mode is its long-scale heartbeat, then Betelgeuse could be ready to blow sooner than expected. However, if its fundamental mode is its short-scale heartbeat, as several studies suggest, then its longer heartbeat is a phenomenon called a long secondary period. In that case, this longer brightening and dimming would be caused by something external to the star. Scientists still don't know for sure what causes long secondary periods, but one leading theory is that they arise when a star has a companion that circles it and barrels through the cosmic dust that is produced and expelled by the star. The displaced dust alters how much starlight reaches Earth, changing the star's apparent brightness. The researchers explored whether other processes may have caused the long secondary period, such as the churning of the star's interior or periodic changes in the star's powerful magnetic field. After combining data from direct observations of Betelgeuse with advanced computer models that simulate the star's activity, the team concluded that Betelbuddy is by far the most likely explanation. "Nothing else added up," Goldberg says. "Basically, if there's no Betelbuddy, then that means there's something way weirder going on—something impossible to explain with current physics." The team has yet to determine exactly what the Betelbuddy is, but they assume it's a star of up to twice the sun's mass. "It is difficult to say what the companion actually is beyond providing mass and orbital constraints," says Joyce. "A sunlike star is the most probable type of companion, but that is by no means conclusive." "A more exotic hypothesis I personally like, though the opinions of my co-authors may differ, is that the companion is a neutron star—the core of a star that has already gone supernova," she says. "However, in that case, we would expect to see evidence of this with X-ray observations, and we haven't. I think we should look again."  Betelgeuse's position in the constellation Orion. Credit: Lucy Reading-Ikkanda/Simons Foundation A new view of an old star Next, the team will play paparazzi, trying to snap images of the Betelbuddy with telescopes, as there will be a potential window of visibility around December 6. "We need to confirm that Betelbuddy actually exists, since our result is based on inference, not on direct detection," says Molnár. "So we're working on observation proposals now." The researchers note that this study was only possible through team science. "Without each of us considering this problem from very different angles—László as an expert in space-based observations and data analysis, Jared as someone who studies and simulates massive stars, and myself as a 1D modeler—the work wouldn't have been possible," says Joyce. "I want to thank the Flatiron Center for Computational Astrophysics in particular for creating an environment in which pulling together such a diverse range of scientists is possible." The team is also excited to have new information about a long-studied celestial body. Betelgeuse "has been the target of countless studies since the dawn of modern astrophysics," says Molnár. "And yet there's still room to make significant new discoveries: in this case, a sunlike star hiding in plain sight, in the immense glare of a red supergiant. That is what excites me the most." | |
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| Jase1Posted at 2024-10-22 18:02:34(8Wks ago) Report Permalink URL | ||
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|  This image of Arp 107, shown by Webb’s MIRI (Mid-Infrared Instrument), reveals the supermassive black hole that lies in the center of the large spiral galaxy to the right. This black hole, which pulls much of the dust into lanes, also display’s Webb’s characteristic diffraction spikes, caused by the light that it emits interacting with the structure of the telescope itself. Perhaps the defining feature of the region, which MIRI reveals, are the millions of young stars that are forming, highlighted in blue. These stars are surrounded by dusty silicates and soot-like molecules known as polycyclic aromatic hydrocarbons. The small elliptical galaxy to the left, which has already gone through much of its star formation, is composed of many of these organic molecules. Image Description: A pair of interacting galaxies. The larger of the two galaxies is slightly right of center, and is composed of a bright, white center and a ring of blue, gaseous filaments. The center of this galaxy shows Webb’s eight-pronged diffraction pattern. There are three filaments of gas and dust moving from the ring toward the center. At the top left of the ring is a noticeable gap, bordered by two large, blue pockets of dust and gas. The smaller galaxy is made of hazy, light blue gas and dust. Many red, green, blue, and yellow galaxies are spread throughout, with some being hazier in composition and others having more defined spiral patterns. Credit: NASA, ESA, CSA, STScI | |
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| SoupPosted at 2024-10-22 23:33:48(8Wks ago) Report Permalink URL | ||
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| Record gamma rays detected at Milky Way's core by Brian Keenan, Los Alamos National Laboratory  GC analysis results. Credit: The Astrophysical Journal Letters (2024). DOI: 10.3847/2041-8213/ad772e At the High-Altitude Water Cherenkov (HAWC) observatory, 13,000 feet above sea level on the Sierra Negra volcano of Mexico, researchers are getting a look into a violent mystery in the Milky Way galaxy. An international research team co-led by Los Alamos National Laboratory observed ultrahigh-energy gamma rays at more than 100 teraelectron volts, tracking their origin to the galactic center for the first time. "These results are a glimpse at the center of the Milky Way to an order of magnitude higher energies than ever seen before," said Pat Harding, physicist at Los Alamos and the Department of Energy's principal investigator for the project. "The research for the first time confirms a PeVatron source of ultrahigh-energy gamma rays at a location in the Milky Way known as the Galactic Center Ridge, meaning the galactic center is home to some of the most extreme physical processes in the universe." The HAWC observatory has been gathering data for more than seven years. In so doing, the researchers have observed nearly 100 gamma-ray events with energy more than 100 teraelectron volts. As described in an analysis led by Sohyoun Yu Cárcaron published in The Astrophysical Journal Letters, that data allows the cosmic ray interactions with the PeVatron to be directly studied and compared with other observations, helping pin down the emission processes and location—right in the center of the Milky Way galaxy. The most violent processes in the universe The actual PeVatron itself remains a not-well-understood phenomenon, but the fact of its existence in whatever form it takes points to the violent regime in the galactic center. That region of the Milky Way galaxy is known to include a supermassive black hole surrounded by neutron stars and white dwarfs that strip material from nearby stars. The area is shrouded with dense gas clouds that reach temperatures of millions of degrees and tend to prevent much direct optical observation of the region. The observation of gamma rays thus proves critical for illuminating the cosmic processes at work in that extreme environment. Ultrahigh-energy gamma rays originate with the presence of a PeVatron source, which accelerates particles to a million billion electron volts (PeV) in energy, a quadrillion times more powerful than the light particles coming out of a light bulb. The cosmic-ray protons generated by the PeVatron travel at more than 99% the speed of light, interacting with dense ambient gas and resulting in ultrahigh-energy gamma rays. The exact nature of the PeVatrons remains a mystery, however. The energies involved point to some of the most violent processes conceivable in the universe: a star's death in a supernova, the shocks and radiation that accompany the fusion-rich birth of a star, a black hole swallowing up another black hole. "A lot of those processes are so rare you wouldn't expect them to be happening in our galaxy, or they occur on scales that don't correlate with the size of our galaxy," Harding said. For instance, a black hole eating another black hole would be an event only expected outside our galaxy." Cherenkov light in particle detection HAWC is a unique experiment designed to capture the relatively few ultrahigh-energy gamma rays that can travel interstellar distances and reach Earth. On the slopes of the Sierra Negra volcano, 300 grain silos are filled with water, the bottom of each silo lined with photomultiplier detectors. When the ultrahigh-energy particles reach Earth's atmosphere, they break up into extensive air showers of lower-energy particles. As the charged particles pass through the tanks at a speed outpacing the water's phase velocity, they produce Cherenkov light, or Cherenkov radiation, a blue glow—an effect somewhat similar to the auditory sonic boom. The researchers then analyzed the time distribution of the particles detected across tanks to understand the energy regimes at play, deducing the origins of the particles as ultrahigh-energy gamma rays. Locating the specific PeVatron site The HAWC observatory experiment has built on the groundbreaking Milagro experiment, a gamma-ray observatory with a 5-million-gallon water pond and 700 light detectors in the Jemez Mountains outside Los Alamos. Milagro took data through 2008, and then researchers moved south to the HAWC observatory to be able to capture particles closer to the galactic center. The research team plans to extend its HAWC observatory findings and narrow down the specific site of the PeVatron source with a new experiment, the Southern Wide-field Gamma-ray Observatory, a facility being built in the Atacama Desert in Chile. With that wider window into the center of the Milky Way, science may have a closer view of the mystery at the heart of our home galaxy. | |
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| Jase1Posted at 2024-10-25 18:32:12(7Wks ago) Report Permalink URL | ||
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| Webb finds candidates for first young brown dwarfs outside the Milky Way  Meet NGC 602, a young star cluster in the Small Magellanic Cloud (one of our satellite galaxies), where astronomers using @NASAWebb have found candidates for the first brown dwarfs outside of our galaxy. This star cluster has a similar environment to the kinds of star-forming regions that would have existed in the early Universe—with very low amounts of elements heavier than hydrogen and helium. It’s drastically different from our own solar neighborhood and close enough to study in detail. Brown dwarfs are… not quite stars, but also not quite gas giant planets either. Typically they range from about 13 to 75 Jupiter masses. They are also free-floating; they aren’t gravitationally bound to a star like a planet would be. But they do share some characteristics with exoplanets, like storm patterns and atmospheric composition. @NASAHubble showed us that NGC 602 harbors some very young low-mass stars; Webb is showing us how significant and extensive objects like brown dwarfs are in this cluster. Scientists are excited to better be able to understand how they form, particularly in an environment similar to the harsh conditions of the early universe. Image description: A star cluster is shown inside a large nebula of many-coloured gas and dust. The material forms dark ridges and peaks of gas and dust surrounding the cluster, lit on the inner side, while layers of diffuse, translucent clouds blanket over them. Around and within the gas, a huge number of distant galaxies can be seen, some quite large, as well as a few stars nearer to us which are very large and bright. Image Credit: ESA/Webb, NASA & CSA, P. Zeidler, E. Sabbi, A. Nota, M. Zamani (ESA/Webb) | |
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| Jase1Posted at 2024-11-01 17:14:38(6Wks ago) Report Permalink URL | ||
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|  Happy Halloween from @NASAWebb and @NASAHubble! This terrifying new image combines data from both telescopes, unveiling a scary pair of “eyes” in space. These eyes are actually the cores of two galaxies. The smaller spiral galaxy on the left is IC 2163. It has been slowly “creeping” behind the larger galaxy, NGC 2207. It’s possible this pair will swing by one another repeatedly over the course of many millions of years. Their cores and arms might eventually meld, leaving behind completely reshaped arms, and an even brighter cyclops-like “eye” at the core. These galaxies are busy places! In just one Earth year,they can form the equivalent of two dozen new stars that are the size of our Sun. That’s a lot compared to our Milky Way, which only forms the equivalent of two or three new Sun-like stars per year. This image’s macabre colors are produced by combining mid-infrared light from Webb with ultraviolet and visible light from Hubble! NASA, ESA, CSA, galaxies take the shape of a colorful beaded mask that sits above the nose. The galaxy at left, IC 2163, is smaller, taking up a little over a quarter of the view. The galaxy at right, NGC 2207, takes up half the view, with its spiral arms reaching the edges. IC 2163 has a bright orange core, with two prominent spiral arms that rotate counter clockwise and become straighter towards the ends, the left side extending almost to the edge. Its arms are a mix of pink, white, and blue, with an area that takes the shape of an eyelid appearing whitest. NGC 2207 has a very bright core. Overall, it appears to have larger, thicker spiral arms that spin counter clockwise. This galaxy also contains more and larger blue areas of star formation that poke out like holes from the pink spiral arms. In the middle, the galaxies’ arms appear to overlap. The edges show the black background of space, including extremely distant galaxies that look like orange and red smudges, and a few foreground stars. Image credit: NASA, ESA, CSA, STScI | |
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| SoupPosted at 2024-11-06 20:14:32(5Wks ago) Report Permalink URL | ||
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| Viewpoint: Carl Sagan's scientific legacy extends far beyond 'Cosmos' by Jean-Luc Margot, The Conversation  On Nov. 9, 2024, the world will mark Carl Sagan's 90th birthday—but sadly without Sagan, who died in 1996 at the age of 62. Most people remember him as the co-creator and host of the 1980 "Cosmos" television series, watched worldwide by hundreds of millions of people. Others read "Contact," his best-selling science fiction novel, or "The Dragons of Eden," his Pulitzer Prize-winning nonfiction book. Millions more saw him popularize astronomy on "The Tonight Show." What most people don't know about Sagan, and what has been somewhat obscured by his fame, is the far-reaching impact of his science, which resonates to this day. Sagan was an unequaled science communicator, astute advocate and prolific writer. But he was also an outstanding scientist. Sagan propelled science forward in at least three important ways. He produced notable results and insights described in over 600 scientific papers. He enabled new scientific disciplines to flourish. And he inspired multiple generations of scientists. As a planetary astronomer, I believe such a combination of talents and accomplishments is rare and may occur only once in my lifetime. Scientific accomplishments Very little was known in the 1960s about Venus. Sagan investigated how the greenhouse effect in its carbon dioxide atmosphere might explain the unbearably high temperature on Venus—approximately 870 degrees Fahrenheit (465 degrees Celsius). His research remains a cautionary tale about the dangers of fossil fuel emissions here on Earth. Sagan proposed a compelling explanation for seasonal changes in the brightness of Mars, which had been incorrectly attributed to vegetation or volcanic activity. Wind-blown dust was responsible for the mysterious variations, he explained. Sagan and his students studied how changes to the reflectivity of Earth's surface and atmosphere affect our climate. They considered how the detonation of nuclear bombs could inject so much soot into the atmosphere that it would lead to a yearslong period of substantial cooling, a phenomenon known as nuclear winter. With unusual breadth in astronomy, physics, chemistry and biology, Sagan pushed forward the nascent discipline of astrobiology—the study of life in the universe. Together with the research scientist Bishun Khare at Cornell University, Sagan conducted pioneering laboratory experiments and showed that certain ingredients of prebiotic chemistry, called tholins, and certain building blocks of life, known as amino acids, form naturally in laboratory environments that mimic planetary settings. He also modeled the delivery of prebiotic molecules to the early Earth by asteroids and comets, and he was deeply engaged in the biological experiments onboard the Mars Viking landers. Sagan also speculated about the possibility of balloon-shaped organisms floating in the atmospheres of Venus and Jupiter. His passion for finding life elsewhere extended far beyond the solar system. He was a champion of the search for extraterrestrial intelligence, also known as SETI. He helped fund and participated in a systematic search for extraterrestrial radio beacons by scanning 70% of the sky with the physicist and electrical engineer Paul Horowitz. He proposed and co-designed the plaques and the "Golden Records" now affixed to humanity's most distant ambassadors, the Pioneer and Voyager spacecrafts. It is unlikely that extraterrestrials will ever find these artifacts, but Sagan wanted people to contemplate the possibility of communication with other civilizations. Advocacy Sagan's scientific output repeatedly led him to become an eloquent advocate on issues of societal and scientific significance. He testified before Congress about the dangers of climate change. He was an antinuclear activist and spoke out against the Strategic Defense Initiative, also known as "Star Wars." He urged collaborations and a joint space mission with the Soviet Union, in an attempt to improve U.S.-Soviet relations. He spoke directly with members of Congress about the search for extraterrestrial intelligence and organized a petition signed by dozens of prominent scientists urging support for the search. But perhaps his most important gift to society was his promotion of truth-seeking and critical thinking. He encouraged people to muster the humility and discipline to confront their most cherished beliefs—and to rely on evidence to obtain a more accurate view of the world. His most cited book, "The Demon-Haunted World: Science as a Candle in the Dark," is a precious resource for anyone trying to navigate this age of disinformation. Impact A scientist's impact can sometimes be gauged by the number of times their scholarly work is cited by other scientists. According to Sagan's Google Scholar page, his work continues to accumulate more than 1,000 citations per year. Indeed, his current citation rate exceeds that of many members of the National Academy of Sciences, who are "elected by their peers for outstanding contributions to research," according to the academy's website, and is "one of the highest honors a scientist can receive." Sagan was nominated for election into the academy during the 1991–1992 cycle, but his nomination was challenged at the annual meeting; more than one-third of the members voted to keep him out, which doomed his admission. An observer at that meeting wrote to Sagan, "It is the worst of human frailties that keeps you out: jealousy." This belief was affirmed by others in attendance. In my opinion, the academy's failure to admit Sagan remains an enduring stain on the organization. No amount of jealousy can diminish Sagan's profound and wide-ranging legacy. In addition to his scientific accomplishments, Sagan has inspired generations of scientists and brought an appreciation of science to countless nonscientists. He has demonstrated what is possible in the realms of science, communication and advocacy. Those accomplishments required truth-seeking, hard work and self-improvement. On the 90th anniversary of Sagan's birth, a renewed commitment to these values would honor his memory. | |
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| SoupPosted at 2024-11-11 19:28:38(5Wks ago) Report Permalink URL | ||
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| Star's disappearance in Andromeda marks the birth of a black hole by Evan Gough, Universe Today  This Illustration shows a failed supernova turning directly into a black hole without an explosion. Credit: NASA/ESA/P. Jeffries (STScI) Massive stars about eight times more massive than the sun explode as supernovae at the end of their lives. The explosions, which leave behind a black hole or a neutron star, are so energetic they can outshine their host galaxies for months. However, astronomers appear to have spotted a massive star that skipped the explosion and turned directly into a black hole. Stars are balancing acts between the outward force of fusion and the inward force of their own gravity. When a massive star enters its last evolutionary stages, it begins to run out of hydrogen, and its fusion weakens. The outward force from its fusion can no longer counteract the star's powerful gravity, and the star collapses in on itself. The result is a supernova explosion, a calamitous event that destroys the star and leaves behind a black hole or a neutron star. However, it appears that sometimes these stars fail to explode as supernovae and instead turn directly into black holes. New research shows how one massive, hydrogen-depleted supergiant star in the Andromeda galaxy (M31) failed to detonate as a supernova. The research, posted to the arXiv preprint server, is titled "The disappearance of a massive star marking the birth of a black hole in M31." The lead author is Kishalay De, a postdoctoral scholar at the Kavli Institute for Astrophysics and Space Research at MIT. These types of supernovae are called core-collapse supernovae, also known as Type II. They're relatively rare, with one occurring about every 100 years in the Milky Way. Scientists are interested in supernovae because they are responsible for creating many of the heavy elements, and their shock waves can trigger star formation. They also create cosmic rays that can reach Earth. This new research shows that we may not understand supernovae as well as we thought. The star in question is named M31-2014-DS1. Astronomers noticed it brightening in mid-infrared (MIR) in 2014. For one thousand days, its luminosity was constant. Then, for another thousand days between 2016 and 2019, it faded dramatically. It's a variable star, but that can't explain these fluctuations. In 2023, it was undetected in deep optical and near-IR (NIR) imaging observations. The researchers say that the star was born with an initial mass of about 20 stellar masses and reached its terminal nuclear-burning phase with about 6.7 stellar masses. Their observations suggest that the star is surrounded by a recently ejected dust shell, in accordance with a supernova explosion, but there's no evidence of an optical outburst. "The dramatic and sustained fading of M31-2014-DS1 is exceptional in the landscape of variability in massive, evolved stars," the authors write. "The sudden decline of luminosity in M31-2014-DS1 points to the cessation of nuclear burning together with a subsequent shock that fails to overcome the infalling material." A supernova explosion is so powerful that it completely overcomes infalling material. "Lacking any evidence for a luminous outburst at such proximity, the observations of M31-2014-DS1 bespeak signatures of a 'failed' SN that leads to the collapse of the stellar core," the authors explain. What could make a star fail to explode as a supernova, even if it's the right mass to explode? Supernovae are complex events. The density inside a collapsing core is so extreme that electrons are forced to combine with protons, creating both neutrons and neutrinos. This process is called neutronization, and it creates a powerful burst of neutrinos that carries about 10% of the star's rest mass energy. The outburst is called a neutrino shock. Neutrinos get their name from the fact that they're electrically neutral and seldom interact with regular matter. Every second, about 400 billion neutrinos from our sun pass right through every person on Earth. But in a dense stellar core, the neutrino density is so extreme that some of them deposit their energy into the surrounding stellar material. This heats the material, which generates a shock wave. The neutrino shock always stalls, but sometimes it revives. When it revives, it drives an explosion and expels the outer layer of the supernova. If it's not revived, the shock wave fails, and the star collapses and forms a black hole. In M31-2014-DS1, the neutrino shock was not revived. The researchers were able to constrain the amount of material ejected by the star, and it was far below what a supernovae would eject. "These constraints imply that the majority of stellar material (≳5 solar masses) collapsed into the core, exceeding the maximum mass of a neutron star (NS) and forming a BH," they conclude. About 98% of the star's mass collapsed and created a black hole with about 6.5 solar masses. M31-2014-DS1 isn't the only failed supernova, or candidate failed supernova, that astronomers have found. They're difficult to spot because they're characterized by what doesn't happen rather than what does. A supernova is hard to miss because it's so bright and appears in the sky suddenly. Ancient astronomers recorded several of them. In 2009, astronomers discovered the only other confirmed failed supernova. It was a supergiant red star in NGC 6946, the "Fireworks Galaxy." It's named N6946-BH1 and has about 25 solar masses. After disappearing from view, it left only a faint infrared glow. In 2009, its luminosity increased to a million solar luminosities, but by 2015, it had disappeared in optical light. A survey with the Large Binocular Telescope monitored 27 nearby galaxies, looking for disappearing massive stars. The results suggest that between 20% and 30% of massive stars can end their lives as failed supernovae. However, M31-2014-DS1 and N6946-BH1 are the only confirmed observations. | |
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