News




Hubble finds hints the Sombrero galaxy had a turbulent past

Thursday, February 27th 2020 03:26 PM

  New data from the Hubble Space Telescope reveals the popular Sombrero galaxy may have had a more violent past than previously thought. Based on the number of metal-rich stars Hubble spotted in the galaxy’s extended halo, astronomers think the seemingly serene Sombrero galaxy could have once went through a major merger with another galaxy.“The Sombrero has always been a bit of a weird galaxy, which is what makes it so interesting,” Paul Goudfrooij, a scientist for the Space Telescope Science Institute, said in a press release.The Sombrero galaxy is a go-to target for amateur observers, largely due to the stunningly smooth brim of its disk, which appears to us nearly edge on. This is where the Sombrero gets its name. But, as with most galaxies, the Sombrero’s stars extend far beyond the galaxy’s disk. This area of space surrounding the “sombrero” is called the halo.Halos are usually packed with old, metal-poor stars. But using Hubb...

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Hubble captures a smeared fingerprint of an "anemic" galaxy

Wednesday, February 26th 2020 02:18 PM

  Looking at this face-on view of the galaxy NGC 4689, as seen by the Hubble Space Telescope, you can barely tell it's a spiral galaxy. Instead, thanks to its relatively dim spiral arms, NGC 4689 looks more like a smeared cosmic fingerprint — especially when compared to some of Hubble's other high-contrast hits.This mottled appearance is because NGC 4689 is an “anemic galaxy,” which is a galaxy that’s deficient in neutral hydrogen, an element crucial for creating new stars. With fewer stars, the spiral arms of NGC 4689 — located some 50 million light-years from Earth — are less bright than the arms of many other spiral galaxies.This foggy view makes it hard to define the edges of each of the galaxy's blended arms, creating the smudged illusion of NGC 4689. However, as noted in a press release, the galaxy undoubtedly still has an "otherworldly charm."

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  The hottest known exoplanet is back in the news, answering some questions about ultra-hot planets, while also raising some new ones. The planet, KELT-9b, was first announced in 2017. It’s roughly three times the mass of Jupiter, orbits its star every day and a half, and is a whopping 7,800 degrees Fahrenheit (4,300 Celsius). Just for the record, that’s hotter than some stars. And according to new research, the planet's dayside is also hot enough to tear apart hydrogen molecules, which astronomers recently observed. Turn to heat evenly Researchers, including Megan Mansfield from the University of Chicago, sought to understand how heat is distributed on this faraway world. So they watched carefully with the powerful (and soon to be decommissioned) Spitzer Space Telescope. Like many close-in planets, KELT-9b is tidally locked to its star, meaning one side of the world is always facing its star, while the other side is permanently facing the chilling bla...

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  In pieces of a meteorite, scientists have found tiny mineral grains that are older than the Sun and the solar system, which formed about 4.6 billion years ago. Some of these “presolar grains,” the researchers found, are between five and seven billion years old, making them the oldest known materials on Earth.  The grains initially formed in interstellar space out of material ejected from mature stars that condensed into dust. The researchers who identified the grains think many of them likely were created following a boom in star formation the Milky Way experienced some seven billion years ago. If confirmed, the new finding demonstrates that researchers can study meteorites to better understand the history of star formation in our galaxy.    Rocky records When small to medium stars (from about 0.5 to 5 times the mass of the Sun) approach the ends of their lives, they expand into red giant stars and blow off their outer layers. Th...

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  For just the second time, scientists have used gravitational waves (ripples in space-time) to detect the merger of two colliding neutron stars. The neutron stars — which each cram roughly the mass of the Sun into a city-sized space — have a combined mass greater than any other pair of neutron stars ever observed. “From conventional observations with light, we already knew of 17 binary neutron star systems in our own galaxy and we have estimated the masses of these stars,” said Ben Farr, a LIGO team member from the University of Oregon, in a press release. “What’s surprising is that the combined mass of this binary is much higher than what was expected.” After the collision of these two particularly hefty neutron stars, researchers say the final merged product was likely massive enough (at 3.4 solar masses) to collapse into a black hole, gobbling up any stray matter and light located nearby. Second pair of colliding neutron sta...

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  Since its launch in 2018, NASA's space-based TESS Telescope has discovered at least 37 confirmed exoplanets and identified more than 1,500 exoplanet candidates. And now, it has uncovered its first Tatooine-like circumbinary planet — a world that orbits two stars instead of one. Astronomers have found only a handful of such circumbinary planets so far. But the new discovery shows that many more of these exotic systems may be located around bright, nearby stars like those TESS is built to study. By finding and investigating more of these systems, astronomers hope to get a better understanding of how binary star systems form and evolve.Researchers announced the discovery on Monday at the 235th meeting of the of the American Astronomical Society in Honolulu.     A tilting orbit The primary objective of TESS (the Transiting Exoplanet Survey Satellite) is to scan nearly the entire sky to hunt for exoplanets loca...

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Over the last few weeks, Betelgeuse, the bright reddish star in the constellation Orion, has dimmed to the faintest it's been in a century. Astronomers have been buzzing with excitement about the event, discussing the star over social media and speculating what might be going on.  The big question on everyone’s mind is whether the star is about to go supernova and explode. That’s probably not what’s about to happen, astronomers say, but they’re still excited to be witnessing behavior they’ve never seen from Betelgeuse before. There’s a lot astronomers still don’t know about the variable behavior of supergiant stars like Betelgeuse, so any strange activity is a chance to learn more about the lives of stars.    A Fading Supergiant For over a century, astronomers have watched Betelgeuse brighten and dim again and again. Betelgeuse is a red supergiant, a star late in its life that has expanded to an enormous size. Bubbles o...

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When the Milky Way erupted in 100,000 supernovae

Thursday, December 26th 2019 02:43 PM

  The European Southern Observatory’s Very Large Telescope in Chile has captured a new glimpse at the history of the center of our Milky Way. Astronomers say they’ve found evidence that there was once a burst of star formation so intense that it created over 100,000 supernova explosions.       According to the new data, the Milky Way was once what astronomers call “a starburst galaxy.” It’s an area commonly seen in other parts of the universe where stars form at a fast rate. About 80 percent of the stars in the center of the Milky Way were formed between 8 billion and 13.5 billion years ago. But about 1 billion years ago, another intense star-formation burst happened, creating many massive new stars. These large stars live shorter lives than small stars. And when large stars die, they explode. So the starburst led to a surge in supernovae and a dramatic period of star formation all at around the same time.  ...

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Giant planet found around tiny white dwarf star, a first

Wednesday, December 4th 2019 03:58 PM

  For the first time, astronomers have discovered evidence for a giant planet orbiting a tiny, dead white dwarf star. And, surprisingly, the Neptune-sized planet is more than four times the diameter of the Earth-sized star it orbits. "This star has a planet that we can't see directly," study author Boris Gänsicke from the University of Warwick said in a press release. "But because the star is so hot, it is evaporating the planet, and we detect the atmosphere it is losing." In fact, the searing star is sending a stream of vaporized material away from the planet at a rate of some 260 million tons per day.      The new discovery serves as the first evidence of a gargantuan planet surviving a star's transition to a white dwarf. It suggests that evaporating planets around dead stars may be somewhat common throughout the universe. And because our Sun, like most stars, will also eventually evolve into a white dwarf, the find could even shed lig...

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Earth may have recently destroyed one of its own minimoons

Wednesday, November 27th 2019 10:23 AM

  The Moon is probably not Earth’s only natural satellite right now. Our planet's gravity regularly captures small space rocks and pulls them into orbit. Astronomers estimate that there's probably a 1-yard-wide “minimoon” orbiting Earth at any given time.  And now, a team of researchers in Australia think they actually spotted one burning up in Earth’s atmosphere in 2016 as a particularly bright meteor, or fireball. It's only the second fireball that scientists suspect came from a minimoon. The team presented their findings in a recent paper published in The Astronomical Journal.   The minimoons next door Astronomers haven't had much more luck finding minimoons in orbit, either. So far, scientists have just spotted one while it was still circling Earth. Starting in 2006, a tiny asteroid called 2006 RH120 stuck around for about 11 months before leaving the Earth-moon system. However, researchers expect they'll find more of these...

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