TRAPPIST-1 c: JWST’s hunt for the atmosphere of the neighboring “twin Venus

TRAPPIST-1 c is an Earth-sized hot world about 40 light-years away. The TRAPPIST-1 system consists of a small, cold star and seven planets orbiting it in a matter of days. The planets are all about the same size as Earth or Venus, and their relatively close proximity to us makes this system an intriguing candidate for an atmospheric search with JWST, an important step toward investigating their suitability for life.

But what has the team of scientists studying this planet been able to find out? What results did they obtain?

Studying the atmosphere of the planet TRAPPIST-1 c

The latest result focuses on TRAPPIST-1 c, the second closest planet to the star. Like TRAPPIST-1 b , the planet receives much more light than Earth. TRAPPIST-1 c is similar to Venus in the amount of radiation it receives, but about 60 percent more massive. The team hoped that, like Venus, it was able to maintain a dense atmosphere. But they found that at best it had a sparse atmosphere of carbon dioxide, though it might not have one at all.

The results are not surprising. The star TRAPPIST -1 is slightly larger than Jupiter and has a mass of about 9 percent the mass of the Sun, and its temperature is 2293 °C (4160 °F). But don’t let that fool you. These cold stars are very active with flares and powerful stellar winds that can strip a planet of its atmosphere.

“We wanted to find out if TRAPPIST-1 c could avoid this fate and if it could retain a substantial atmosphere and perhaps even be similar to the planet Venus in the solar system,” lead author Sebastian Zieba, a graduate student at Max. This is according to a statement from the Planck Institute for Astronomy (MPIA) .

“We can definitely rule out the presence of a dense and Venus-like atmosphere,” added Laura Kreidberg, lead scientist of the JWST observing program and co-author and director of MPIA.

So far, they can rule out a thick atmosphere for sure, but their models very broadly allow for an atmosphere rich in carbon dioxide and oxygen, from 1 to 100 percent of Earth’s sea level pressure. More data is needed. Although JWST is the most powerful space observatory ever launched, studying small exoplanets and their atmospheres is very difficult.

“Observations of a rocky planet’s thin atmosphere push JWST to its limits,” Kreidberg explained.

Interesting facts about TRAPPIST-1

– The TRAPPIST-1 system was discovered in 2016 using the TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope).
– All seven planets of the TRAPPIST-1 system were discovered within one year.
– Five of the seven planets are in the habitable zone of the star, where liquid water can exist.
– TRAPPIST-1 is a red dwarf, which is the most common type of star in our Galaxy.
– The distance between TRAPPIST-1 and Earth is about 39 light years.


The nearby planetary system TRAPPIST-1 is currently the best candidate for studying the atmospheres of Earth-type rocky planets orbiting a red dwarf. Although the results of TRAPPIST-1 c atmosphere studies have not shown a dense and Venus-like atmosphere, scientists continue to investigate the remaining planets in the system. Hopefully, in the near future, we will be able to get more data about these mysterious planets and learn more about the possibility of life elsewhere in the universe.

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