baltimore — When the James Webb Space Telescope was first conceived, exoplanets hadn’t even been discovered. Now the observatory is showing astronomers what it can learn about planets — including asteroids — orbiting other stars.
Since its launch in December 2021, JWST has “smell” the atmosphere Jupiter-sized planets orbit very close to their stars (Number: 22/8/26). Those intense worlds are interesting, but not where astronomers hope to look for signs of life.Astronomers will be at the First scientific results from JWST Meeting.
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JWST has also set out to find new rocky worlds.
These early peeks at distant worlds haven’t revealed much about these remote regions. But researchers are encouraged by the discovery of smaller planets outside our solar system that JWST’s keen insight in infrared wavelengths may eventually uncover.
“The main message is, we’re in business,” says Björn Benneke, an astronomer at the University of Montreal. “We don’t even have all the observations yet, but they’re pretty exciting.”
One of the smaller planets observed by the JWST is GJ 1214b, which has frustrate astronomers since its discovery Discovered in 2009 (Serial Number: 12/16/09). The planet is a sub-Neptune, meaning it is somewhere between a rocky world like Earth and a gaseous world like Neptune.
“What the hell are sub-Neptunes?” asks Eliza Kempton, an astronomer at the University of Maryland, College Park.They could be rocky balls with a thick atmosphere of hydrogen and helium, or perhaps water World (Serial Number: 2/22/12). “What we want to do with atmospheric signatures is measure their atmospheres to see which is which,” Kempton said.
Previously, astronomers tried to observe the composition of GJ 1214b’s atmosphere by observing how starlight filtered through it.but the atmosphere is Thick and hazyhampering astronomers’ ability to detect individual molecules in them.
Instead of watching a planet pass in front of its star, Kempton and colleagues used the JWST to look for the glow of a planet before it disappears behind star. It worked: After 38 hours of observations, the researchers detected the planet’s infrared light, Kempton said in a Dec. 13 presentation.
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There’s more work to be done, but preliminary data suggest the planet has a lot of chemistry, possibly including water and methane. It is also rich in elements heavier than hydrogen and helium.
As for knowing what kind of world GJ 1214b is, “I’d say we don’t quite understand it yet,” Kempton said. It could be a water planet, or a gaseous planet that has lost a lot of its light elements, she said.
The telescope also saw the tantalizing for the first time TRAPPIST-1 systemIn another presentation on December 13, Benneke said (Serial Number: 12/13/17). Discovered in 2017, the system contains seven possibly rocky Earth-sized worlds. Three of these planets may have surface temperatures suitable for liquid water, making them particularly interesting targets for JWST and other telescopes looking for signs of life.
But TRAPPIST-1 is a small red star called an M dwarf, a type of star notorious for its violent flares and intense radiation.For years, astronomers have debated whether Planets around these stars would be suitable for lifeor if the star takes away its planet’s atmosphere (Serial Number: 6/14/17).
“If TRAPPIST planets don’t have atmospheres, then we need to continue” the search for extraterrestrial life from M-type dwarfs, said astronomer Mercedes López-Morales of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who was not involved in the new JWST. observe.
JWST’s first observation of one of these potentially habitable worlds, TRAPPIST-1g, did not find any obvious signs of an atmosphere. But the telescope only observed the planet for about five hours. With more observations, it should be possible to detect the atmosphere, if it exists, Benneke said.
JWST is also getting into the planet-hunting game, astronomer Kevin Stevenson said Dec. 14. The telescope double-checked a potentially interesting observation from another telescope and confirmed that it saw a rocky Earth-sized world around the nearby M dwarf star. This proves that JWST has the precision to find such worlds.
“This is an exciting result, perhaps the first exoplanet discovery by JWST,” said Stevenson of the Space Telescope Science Institute in Baltimore. The planet orbits its dim star every two days, so it likely has a surface temperature of about 225 degrees Celsius — probably too hot to be habitable, he said. “It’s more like alien Venus than alien Earth.”
The researchers stress that while it’s still early days, the predictions for finding planets using JWST are good.
The results also pave the way for future observatories, said John Mather, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Wishlist for future tasks A telescope is included to further dig out details of potentially habitable worlds.
“If it’s not impossible,” Mather said, “let’s do it.”