Latest news with #ThomasEvans-Soma
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18 hours ago
- General
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James Webb Space Telescope unveils fiery origins of a distant, hellish exoplanet
When you buy through links on our articles, Future and its syndication partners may earn a commission. Astronomers using NASA's James Webb Space Telescope (JWST) have uncovered the tumultuous history of a distant, hellishly hot exoplanet that's being stretched and scorched by its star. The planet, known as WASP-121b, is locked in a dangerously close orbit around a star roughly 900 light-years away that's brighter and hotter than our sun. Locked in a blistering 30-hour orbit, the world lies so close to its star that intense tidal forces have warped it into a football-like shape, leaving it on the verge of being torn apart by gravity. One side of the planet faces its star permanently, baking at temperatures over 3,000°C (5,400°F) — hot enough for it to rain liquid iron. Even the opposite hemisphere, locked in eternal night, simmers at 1,500°C (2,700°F). This extreme environment makes WASP-121b one of the most hostile planets ever observed, and a valuable target for planetary science. Now, using the James Webb Space Telescope's (JWST) Near Infrared Spectrograph instrument, or NIRSpec, a team led by astronomer Thomas Evans-Soma of the University of New Castle in Australia detected a cocktail of molecules in the planet's atmosphere that each carry chemical clues to its dramatic journey. These include water vapor, carbon monoxide, methane and, for the first time ever in a planetary atmosphere, silicon monoxide. Together, they tell a dramatic origin story of WASP-121b written in vapor and stone, described in two papers published Monday (June 2). "Studying the chemistry of ultra hot planets like WASP-121b helps us to understand how gas giant atmospheres work under extreme temperature conditions," Joanna Barstow, a planetary scientist at the Open University in the U.K. and a co-author of both new studies, said in a statement. The findings from both studies suggest WASP-121b did not form where it is today. Instead, it likely originated in a colder, more distant region of its planetary system, similar to the zone between Jupiter and Uranus in our own solar system. There, it would have accumulated methane-rich ices and heavy elements, embedding a distinct chemical signature in its growing atmosphere. Later, gravitational interactions — possibly with other planets — would have sent WASP-121b spiraling inward toward its star. As it moved closer, its supply of icy, oxygen-rich pebbles would've been cut off, but it should have been able to continue gathering carbon-rich gas. This would explain why the world's atmosphere today contains more carbon than oxygen, a chemical imbalance that offers a snapshot of its journey through the disk. To make sense of the complex atmospheric data, the second team of researchers, led by Cyril Gapp of the Max Planck Institute for Astronomy in Germany, created 3D models of the planet's atmosphere, accounting for the vast temperature differences between the day and night sides. Their simulations, described in a paper published in The Astronomical Journal, helped separate signals from different regions of the planet as it orbited, revealing how molecules shift and circulate throughout the orbit. Among the molecules newly detected, the presence of silicon monoxide was particularly revealing, scientists say, as it isn't typically found in the gaseous form they observed. Instead, the researchers suggest this gas was originally locked in solid minerals like quartz within asteroid-size planetesimals that crashed into the young planet. Over time, as the planet grew and spiraled inward toward its star, those materials would have been vaporized and mixed into its atmosphere, according to one of the new papers, published in Nature Astronomy. Related Stories: — Scientists question possible signs of life on exoplanet K2-18b in new study: 'We never saw more than insignificant hints' — Scientists found a possible new dwarf planet — it could spell bad news for Planet 9 fans — Exoplanet 'baby pictures' reveal exomoons possibly taking shape around infant worlds On the cooler "night" side of WASP-121b, the researchers found an abundance of methane gas. This came as a surprise as methane typically breaks down under such heat, the study notes. "Given how hot this planet is, we weren't expecting to see methane on its nightside," study co-author Anjali Piette, who is an assistant professor of astronomy at the University of Birmingham, said in a statement. Its presence suggests methane is being replenished, likely pulled up from deeper, cooler layers of the atmosphere. "This challenges exoplanet dynamical models, which will likely need to be adapted to reproduce the strong vertical mixing we've uncovered on the nightside of WASP-121b," study lead author Thomas Evans-Soma of the University of New Castle in Australia added in another statement.
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4 days ago
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Tiny Pebbles Created One of The Most Extreme Worlds in The Galaxy
The tiny pebbles left over from a star's formation fed the growth of one of the strangest, wildest worlds humanity has ever known. It's a famous one, Tylos, or WASP-121b, a gas giant exoplanet some 880 light-years away, so close to its host star that its atmosphere is filled with clouds of vaporized metal. Now, new observations show that this world – one of the most studied in the Milky Way – was constructed from the dust and rocks that circled the star, back when the system was still in its early formative years. The smoking gun? Silicon monoxide – clouds of vaporized rock. Using JWST, a team of astronomers identified the molecule in the exoplanet's atmosphere, in addition to water, carbon monoxide, and methane. "The relative abundances of carbon, oxygen, and silicon offer insights into how this planet formed and acquired its material," explains astronomer Thomas Evans-Soma of the University of Newcastle in Australia, who led the research. Tylos is around 1.75 times the radius but only 1.16 times the mass of Jupiter, orbiting a yellow-white star named Dilmun that's 1.5 times the radius of the Sun, on a breakneck orbit of just 30 hours. It's so close to the star that it's literally evaporating, its atmosphere puffed up by the intense heat. As it whips around Dilmun, Tylos passes between us and it, which means it's in the perfect configuration for study. Some of the star's light passes through the exoplanet's puffy atmosphere and becomes altered by the molecules therein as it goes. Astronomers can painstakingly study these tiny signals to figure out which molecules are responsible for the alterations. Tylos is what is known as a hot Jupiter – gas giant worlds in bogglingly close proximities to their host stars. They're something of an open question: they can't form in those close orbits, because the radiation and winds from the star would stop the gas from accumulating. The leading explanation is that they form farther away and migrate inwards. The first detection of silicon monoxide in an exoplanet's atmosphere was described in a paper published in 2022. It's a very difficult and rare molecule to detect. But it's the combination of molecules in the atmosphere of Tylos that helped Evans-Soma and his team figure out the exoplanet's birthplace. Stars are born from dense clouds of molecular gas. As they spin, material arranges itself in a disk that spools into and feeds the growing star. Once the star is powerful enough to push away the material with its winds, its growth is cut off, and the material that's left in the disk clumps in small pebbles of dust and ice that stick together and grow to form planets. At closer proximities to the host star, ice sublimates into gas. This is known as the ice line or the snow line, and different ices have different sublimation points. Studying the ratios of the molecules in the atmosphere of Tylos, the researchers concluded that the exoplanet formed at a distance from its star where methane was in its vapor form, but ice remained frozen. In the Solar System, that distance is out between the orbits of Jupiter and Uranus. Dilmun is hotter than our Sun, so the distance would be even greater for Tylos – suggesting that it had to migrate a long way to get to its current position. It's also some of the best evidence yet for how hot Jupiters form and evolve. But there's another mystery. The methane was detected on the exoplanet's nightside, which faces permanently away from Dilmun. Methane is unstable at high temperatures, and would be undetectable on the scorching dayside. As it moves around into the nightside, it's expected to remain undetectable at the same altitude. The plentiful abundance, therefore, of methane high in the nightside atmosphere of Tylos suggests some interesting atmospheric processes going on. The researchers think it's vertical mixing – strong updrafts carrying methane from deep in the atmosphere to the upper atmosphere, where it can be detected by JWST. "This challenges exoplanet dynamical models, which will likely need to be adapted to reproduce the strong vertical mixing we've uncovered on the nightside," Evans-Soma says. Although we've peered at Tylos more than most of the nearly 6,000 exoplanets confirmed to date, the strange, melting world still has a lot to teach us about planets in the Milky Way. The research has been published in Nature Astronomy. Haunting Image Shows The Moon Deimos From The Surface of Mars Stunning Images Reveal The Sun's Surface in Unprecedented Detail The Universe's Most Powerful Cosmic Rays May Finally Be Explained
