Earth-like planet

SPACE — Five years ago, NASA’s infrared Spitzer Space Telescope helped discover seven rocky exoplanets orbiting the same star, TRAPPIST-1. The planetary system was so similar to ours that it immediately caught the attention of scientists.

Currently, NASA’s new infrared telescope, the James Webb Space Telescope (JWST) is measuring the temperature of one such world, TRAPPIST-1b, which is very similar to Earth. The new research has been published in the journal Nature.

The bad news is that Earth’s twin is almost certainly uninhabitable. Astronomers use JWST’s mid-infrared camera, called MIRI, to look for planetary thermal emissions. They found TRAPPIST-1b to be very hot, with temperatures around 450 degrees Fahrenheit, or 232 degrees Celsius (roughly the temperature of an oven). Most likely the planet also has no atmosphere.

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The find was another first record-breaker from Webb. The most powerful telescope has continued to produce newsworthy achievements since its launch in 2022.

“This is the first detection of any form of light emitted by an exoplanet as small and cold as a rocky planet in our solar system,” NASA officials said in a statement.

“No previous telescope had the sensitivity to measure such dim mid-infrared light,” said Thomas Greene, a NASA astrophysicist and lead author of the new work.

The initial discovery of seven TRAPPIST-1 exoplanets sparked great excitement in the astronomy community. This is because all the distant planets are the size of Earth and are located in the habitable zone of their stars. The habitable zone is the region that is the right distance from the star for liquid water to exist on a planet’s surface.

“The TRAPPIST-1 system is a great laboratory and the best target we have for viewing the atmospheres of rocky planets,” said study co-author Elsa Ducrot, an astronomer at the French Alternative Energies and Atomic Energy Commission (CEA).

However, don’t get too excited that the new world is feasible for humans. The planet TRAPPIST-1 is beyond human reach today, at a distance of 378 billion kilometers. They also orbit a much smaller and redder star than our sun, known as an M dwarf star.

“There are ten times more stars like this in the Milky Way than stars like the sun, and they are twice as likely to have rocky planets than stars like the sun,” Greene said.

These abundant M dwarfs, or M-dwarfs, are an obvious target for astronomers looking for habitable planets. It’s also easier for scientists to observe rocky planets around these smaller stars. However, there is one catch: M dwarfs are much more active than our sun. It often flares up and spews out high-energy rays that can damage developing extraterrestrial life or the atmospheres of planets orbiting it.

Previous observations of TRAPPIST-1b have not been sufficient to determine whether it has an atmosphere, or whether it is barren rock. The planet is tidally locked to its star, meaning one side is always facing its star and the other side is stuck in perpetual night. Simulations show that if the world had an atmosphere, the planet’s temperature would be lower because the air would redistribute heat on both sides.

Read: TRAPPIST-1, Another Solar System with 7 Earth Twin Planets

However, JWST recorded much hotter temperatures, indicating no atmosphere. That removes one more planet from the list of worlds that might be habitable to humans.

Although TRAPPIST-1b has been specifically determined to be uninhabitable, scientists have another perk. Most importantly, the Webb Telescope is capable of making such measurements and will continue to do so, exploring the atmospheres and temperatures of many other worlds.

“There’s one target I’ve envisioned, and it’s this one (TRAPPIST-1b). This is the first time we’ve been able to detect emissions from a rocky, temperate planet. This is a very important step in the story of exoplanet discovery,” said study co-author , Pierre-Olivier Lagage. He is one of the developers of MIRI, the instrument that makes these observations. Source: LiveScience