Latest news with #ZTFSLRN-2020
Yahoo
20-04-2025
- Science
- Yahoo
James Webb Spots Disturbing Sight: Entire Planet Sinking Into Star
Astronomers using the James Webb Space Telescope appear to have made the first-ever direct observation of a star swallowing a planet. Clearly the stellar host was the culprit of this gruesome crime. Acts of "planetary engulfment" occur when a star enters its red giant stage — as our own Sun is fated to do — in a period near the end of its stellar evolution in which it slowly cools and puffs outward, dooming any world it eventually touches. But the astronomer's new study published in The Astrophysical Journal suggests otherwise. They discovered signs that it was actually the ill-fated planet that charged headlong into its own star, in an act of planetary suicide. "Because this is such a novel event, we didn't quite know what to expect when we decided to point this telescope in its direction," said lead author Ryan Lau, an astronomer at the NSF NOIRLab in Arizona, in a statement about the work. Residing some 12,000 light years away, researchers first spotted signs of the star, ZTF SLRN-2020, engulfing a planet in 2023. The telltale was a bright flash of light that betrayed the presence of dust, likely the remains of a disemboweled quondam world. What's more, early evidence suggested that the star was like our Sun, and was entering into its red giant stage. It was coming together. By all accounts, they had caught ZTF SLRN-2020 red handed, and decided to get a second look with the James Webb. "If this was the first directly detected planetary engulfment event, what better target is there to point at?" Lau told Science. Using the orbital observatory's Mid-Infrared Instrument, though, they made a surprising discovery. The star was simply not bright enough to be a red giant, blowing the case wide open. If it wasn't a red giant, then it couldn't have puffed outward to swallow anything. Instead, the team believes that the planet was a Jupiter-sized world that orbited close to the star to begin with, perhaps even closer than Mercury orbits our Sun. Disruptions in the tidal forces between the two bodies led the planet to be nudged inward over millions of years. "The planet eventually started to graze the star's atmosphere," said coauthor Morgan MacLeod, a Harvard astrophysicist, in the statement. "Then it was a runaway process of falling in faster from that moment." As it met its face, the planet took a chunk out of its star, too, blasting some of its outer layers into space with the impact. Eventually, the ejecta cooled into a ring of cold dust encircling the star. But the bloodstain pattern doesn't quite add up. In another twist, the researchers also found another circumstellar ring of hot molecular gas even closer to the star, resembling a planet-forming region more than it does the vestiges of a vaporized world. In any case, there's a lot for the astronomers to chew on. Is this what the crime scene of a planetary engulfment typically looks like? And is this a more common form of demise than the red giant hypothesis? "This is truly the precipice of studying these events. This is the only one we've observed in action, and this is the best detection of the aftermath after things have settled back down," Lau said in the statement. "We hope this is just the start of our sample." More on Webb discoveries: Fearless James Webb Telescope Stares Down "City Killer" Asteroid That Had Been Feared to Strike Earth
Yahoo
14-04-2025
- Science
- Yahoo
Astroforensics Reveals Surprise Twist in Death of Planet Swallowed by Star
A surprise twist has emerged in the tale of an exoplanet that was devoured by its star. Rather than the star expanding to engulf the poor defenseless world, the world itself was complicit in its demise, falling in towards the star on a spiraling orbit of doom. The finding, revealed through observations from JWST, offers some insight into the evolution of planetary systems, and the wild ways they can behave. "Because this is such a novel event, we didn't quite know what to expect when we decided to point this telescope in its direction," says astronomer Ryan Lau of NOIRLab in the US. "With its high-resolution look in the infrared, we are learning valuable insights about the final fates of planetary systems, possibly including our own." The event first caught the attention of astronomers in 2020, when a star 12,000 light-years away suddenly blazed with light, brightening by a factor of 100 before rapidly fading again. By carefully analyzing all the possibilities, scientists concluded that the event, named ZTF SLRN-2020, could only be the result of a star scarfing down one of its exoplanets. This is a Big Deal. It was the first time astronomers had observed a star devouring one of its orbiting worlds, opening what we thought was a window into the final stages of the life of a planetary system as a Sun-like star puffs up into a red giant and engulfs the exoplanets orbiting it. "We are seeing the future of the Earth," astrophysicist Kishalay De of MIT's Kavli Institute for Astrophysics and Space Research said at the time. Only, well, that turns out not to have been the case at all. Lau and his colleagues turned JWST's mid-infrared and near-infrared instruments to the star to reveal a completely different story. When a star is just living its life, fusing atoms in its core to make heavier elements, it exists on the main sequence stage of a star's lifetime. When a Sun-like star starts to run out of its fuel, it puffs up into a red giant. It becomes hotter, brighter, larger: an unstable giant on the brink of death. Any worlds within range would be toast; the Sun, scientists believe, might puff up as far as the orbit of Mars when it reaches the red giant phase in a few billion years. However, when looking at the star responsible for ZTF SLRN-2020, JWST's mid-infrared instrument (MIRI) found that this star was nowhere near as bright as it should be if it was at the red giant phase. Rather, its brightness was consistent with a K-type star around 70 percent of the mass of the Sun, an orange dwarf with a main sequence lifespan up to 70 billion years. In other words, it's a smallish, dimmish, coolish star that's still comfortably sitting on the main sequence. There's no puffing, there has been no puffing, and there will be no puffing for a long time. Which means that the exoplanet had to have died some other way. There's a category of exoplanets out there that can explain it. A surprising number of 'hot Jupiters' exist in the Milky Way. These are Jupiter-sized worlds that are orbiting their stars extremely closely – too close to have been able to form there. We have even seen hot Jupiters on such close orbits that they are evaporating, creating long tails of material as they whirl around their star. This could be one of the earliest stages of devourment: the exoplanet loses mass, its orbit decays further, and it ultimately slams into the star and dies. This is what Lau and his colleagues think happened with ZTF SLRN-2020. A Jupiter-sized world was on a close orbit, closer than that of Mercury, that gradually decayed over millions of years, until it reached the point of total devastation. "The planet eventually started to graze the star's atmosphere. Then it was a runaway process of falling in faster from that moment," says astronomer Morgan MacLeod of the Harvard-Smithsonian Center for Astrophysics and the Massachusetts Institute of Technology. "The planet, as it's falling in, started to sort of smear around the star." Eventually, it disappeared into the star, leaving behind a puff of gas that cooled into cold molecular gas. Observations with NIRSpec revealed something unexpected, though. Closer to the star than the cool gas was a cloud of hot molecular gas that contained molecules such as carbon monoxide and phosphine. The carbon monoxide, in particular, was interesting: it bore a powerful resemblance to the carbon monoxide seen in the planet-forming disks of dust that surround baby stars. What its presence at a planetary death means remains to be studied. "This is truly the precipice of studying these events. This is the only one we've observed in action, and this is the best detection of the aftermath after things have settled back down," Lau says. "We hope this is just the start of our sample." The research has been published in The Astrophysical Journal. Striking Evidence of Water Imbalance on The Moon Hints at a Collision 21 Heartwarming Images Reveal The Human Side of Life in Space 'Hidden Galaxies' Exposed by Deep Sky Map Could Solve Energy Mystery
