Five years ago, NASA’s infrared Spitzer Space Telescope helped discover a family of seven rocky exoplanets orbiting the same star known as Trappist-1. Now, NASA’s new infrared powerhouse — the James Webb Space Telescope (JWST) — has measured the temperature of one of those worlds, Trappist-1b, in a new study published in the journal Nature. (opens in new tab).
The bad news: an Earth-like planet is almost certainly uninhabitable.
Astronomers used JWST’s mid-infrared camera, called MIRI, to look for the planet’s heat emission — think heat-sensing “Terminator” vision. They found that TRAPPIST-1b is burning — at about 450 degrees Fahrenheit (232 degrees Celsius), about the temperature of an oven — and likely lacks an atmosphere.
The discovery is another record-breaking first for JWST, which has been producing continuously Newsworthy results Since its launch
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“This is the first detection any A form of light emitted by an exoplanet as small and cool as a rocky planet in our own solar system,” NASA officials said. statement (opens in new tab).
“No previous telescopes have had the sensitivity to measure such faint mid-infrared light,” Thomas Greene (opens in new tab)a NASA astrophysicist and lead author of the new work, said in the statement.
The initial discovery of the seven Trappist-1 exoplanets caused great excitement in the astronomical community, as all distant worlds are Earth-sized and located in the habitable zone of their star, the region at the right distance from a star. Liquid water exists on the surface of a planet. The system is “a great laboratory” and “our best target for looking at the atmospheres of rocky planets,” study co-author Elsa Ducrot (opens in new tab)An astronomer at the French Alternative Energy and Atomic Energy Commission (CEA) said in a statement.
Don’t get too excited about a new world for humans just yet, though — the TRAPPIST-1 planets are beyond our current reach, 235 trillion miles (378 trillion kilometers) away. They orbit a star much smaller and redder than our Sun, known as an M dwarf star.
“There are ten times more of these stars than Sun-like stars in the Milky Way, and twice as likely to have rocky planets as Sun-like stars,” Greene said.
These abundant M dwarfs are obvious targets for astronomers looking for habitable planets, and observing rocky planets around these small stars is conveniently easy. There’s a catch, though: M dwarfs are much more active than our Sun, burn more often, and emit high-energy rays that could be harmful to budding extraterrestrial life or planetary atmospheres.
Previous observations of TRAPPIST-1b were not sensitive enough to determine whether it had an atmosphere or whether it was a barren rock. The planet is tidally locked to its star, meaning one side always faces its star and the other Stuck in eternal night. The simulations suggest that if this Earth had an atmosphere, the temperature of the planet would be lower, because the air would redistribute the heat in both directions. JWST recorded a significantly hotter temperature, though – no atmosphere and knocked another planet off the list of possibly habitable worlds.
The real excitement here, however, isn’t really the specifics of TRAPPIST-1b. Instead, the important way is that JWST is able to make these kinds of measurements and will continue to make more by exploring the atmospheres and temperatures of many other worlds.
“There was one goal that I dreamed of, and this was it,” said the study’s co-author. Pierre-Olivier’s luggage (opens in new tab), also with CEA, said in the statement. Lagage is one of the developers of MIRI, the instrument that made these observations “This is the first time we can detect emission from a rocky, temperate planet. This is a really important step in the exoplanet discovery story.”
