Located about 40 light-years away, the TRAPPIST-1 system is home to seven other planets similar to Earth in size, mass, and density.
An international group of astronomers managed to measure the temperature of the rocky exoplanet TRAPPIST-1b, a celestial body many scientists liken to Earth, using NASA’s James Webb telescope.
The study, published Monday in the journal Nature, revealed that the planet probably don’t have a significant atmosphereand that the temperature of its day side is about 230°C. Although the finding may sound disappointing, the scientists highlight the power of Webb’s technology, which opens the door for more results in the study of the TRAPPIST-1 system.
The conclusions are based on the planet’s thermal emission, observed by Webb in mid-infrared wavelengths of light, 20 times redder than what the human eye can see, to determine how it changed as TRAPPIST-1b moved behind. from its host star. By measuring the brightness of the star and planet together, compared to that of the star alone, astronomers were able to calculate how much was coming from the planet.
“These observations really take advantage of the Webb’s mid-infrared capabilitysaid Thomas Greene, an astrophysicist at NASA Ames Research Center and lead author of the study.
The TRAPPIST-1 system, located about 40 light-years away, is home to a group of seven planets similar to Earth in size, mass, and density. Three of them are inside the so-called habitable zone of the star, not so close that all liquid water boils, nor so far as to freeze.
TRAPPIST-1b is the innermost planet in the system and orbits its Sun at a distance of about “one-hundredth that of Earth”, so “receives four times the amount of energy” solar energy that reaches our planet, details NASA. Although not within the system’s habitable zone, observations can provide important information about its sister planets, as well as those of other M dwarf systems (the smallest known type of star capable of burning hydrogen at its cores). .
“There are 10 times more of these stars in the Milky Way than stars like the Sun, and they are twice as likely as the latter to have rocky planets,” Greene explained. “But they’re also very active: they’re very bright when they’re young, and they give off flares and X-rays that can destroy an atmosphere,” she added.
This is the first detection of any form of light emitted by an exoplanet as small and cold as the rocky planets in our own solar system, so the findings mark an important step in determining whether those orbiting small active stars, such as TRAPPIST- 1, can sustain the necessary atmospheres to host forms of life.