Mashable has the details, but the general gist is the space telescope will not focus on Sun-like stars to find Earth-like planets (that is, rocky worlds with gaseous atmospheres). Instead, a new project is seeking air-supporting planets around red dwarf stars:
Despite red dwarfs’ potential, no one knows for sure whether their worlds can have atmospheres, or what chemicals could be within their air.
Scientists will soon begin to answer those questions with the James Webb Space Telescope, a partnership of NASA and its European and Canadian counterparts. A new large-scale program will budget about 500 hours for observing rocky exoplanets orbiting small red stars, specifically to search for atmospheres.
Though the survey is designated for Webb’s fourth research cycle, which starts next July, observations may begin sooner, said Néstor Espinoza, an astronomer heading the program’s implementation team.
“This is one of those high-risk, high-reward programs,” he told Mashable. “Imagine that for all of the targets, we detect atmospheres. Then you answer the question, ‘Yes, atmospheres are very common around these stars. That means maybe life can emerge.’ On the other hand, if you found out that none of them have atmospheres, that would be pretty sad, but also pretty interesting. It would mean that our planetary system is actually really, really special.”
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The new campaign will allow scientists to survey 10 to 20 rocky worlds, with an emphasis on planets between 200 and 450 Kelvin. For comparison, Earth is 288 Kelvin, or an average 59 degrees Fahrenheit. Most of the targets will be less than twice the size of Earth. The Space Telescope Science Institute will put out a call for advisers to help determine the target list.
For Kevin Stevenson, an astrophysicist at Johns Hopkins Applied Physics Laboratory, the wishlist would include GJ 486 b, a world he has previously studied, and LTT 1445 A b, one of the nearest strong cases for having air. He believes the Webb campaign will advance humans’ understanding of rocky worlds by a decade.
“This survey program will be the next major step towards answering the question, ‘Are we alone?'” Stevenson said in an email. “Without an atmosphere, it’s hard to see how life, at least as we know it, can survive on a planet.”
If most M-dwarf-orbiting planets turn out not to have an atmosphere, then a future instrument, the Habitable Worlds Observatory, becomes all the more important in the search for life beyond this solar system, he said. The Hubble-esque telescope is expected to focus on terrestrial worlds orbiting sun-like stars.