Using the James Webb Space Telescope (JWST), astronomers have confirmed that the planetTRAPPIST-1b probably has no atmosphere. Researchers have been excited to explore it and its six siblings(兄弟姐妹). The system is a unique laboratory for studying how environmental conditions arise on planets—and how they might become suitable for life.
JWST searched for an atmosphere on TRAPPIST-1b by looking for heat radiating from it. With the telescope's ability to study infrared(红外线的) light, "you can actually measure the glow of the planet, says Thomas Greene, an astronomer at NASA's Ames Research Center.
Although the finding might sound disappointing to those hoping for an atmosphere, scientists say that the work showcases JWST's transformational power and opens the door for more results from the TRAPPIST-1 system.
JWST looked at TRAPPIST-1 in mid-infrared wavelengths of light to see how that radiation changed as TRAPPIST-1b moved behind the star. By measuring the brightness of the star and planet together compared with that of the star alone, astronomers could calculate how much came from the planet.
If TRAPPIST-1b had an atmosphere, it would have distributed the energy absorbed from the star and appeared less bright than Greene and his colleagues measured. The observations did not reveal any carbon dioxide on the planet, which JWST might have been able to spot.
It's not surprising that TRAPPIST-1b has no atmosphere, because it receives four times as much radiation as Earth from the Sun. TRAPPIST-1 is also suffering from stellar flares(恒星耀斑) and other activity that sends radiation across its planets, potentially driving away atmospheres.
More discoveries are sure to come. Other research teams have been using JWST to studyTRAPPIST-1b, as well as other planets in the system. That includes TRAPPIST-1b's neighbor, TRAPPIST-1c, a planet that is close enough to its star for JWST to study its glow. Publications on all of these are expected soon.
