Research finds exoplanet TRAPPIST-1e is unlikely to have a Venus- or Mars-like ambiance | MIT Information

In the seek for liveable exoplanets, atmospheric situations play a key function in figuring out if a planet can maintain liquid water. Suitable candidates typically sit within the “Goldilocks zone,” a distance that’s neither too shut nor too removed from their host star to permit liquid water. With the launch of the James Webb Space Telescope (JWST), astronomers are amassing improved observations of exoplanet atmospheres that can assist decide which exoplanets are good candidates for additional research.

In an open-access paper published today in The Astrophysical Journal Letters, astronomers used JWST to take a more in-depth have a look at the ambiance of the exoplanet TRAPPIST-1e, positioned within the TRAPPIST-1 system. While they haven’t discovered definitive proof of what it’s manufactured from — or if it even has an environment — they had been in a position to rule out a number of prospects.

“The idea is: If we assume that the planet is not airless, can we constrain different atmospheric scenarios? Do those scenarios still allow for liquid water at the surface?” says Ana Glidden, a postdoc within the MIT Department of Earth, Atmospheric and Planetary Sciences (EAPS) and the MIT Kavli Institute for Astrophysics and Space Research, and the primary writer on the paper. The solutions they discovered had been sure.

The new information rule out a hydrogen-dominated ambiance, and place tighter constraints on different atmospheric situations which are generally created via secondary-generation, corresponding to volcanic eruptions and outgassing from the planet’s inside. The information had been constant sufficient to nonetheless enable for the opportunity of a floor ocean.

“TRAPPIST-1e remains one of our most compelling habitable-zone planets, and these new results take us a step closer to knowing what kind of world it is,” says Sara Seager, Class of 1941 Professor of Planetary Science at MIT and co-author on the research. “The evidence pointing away from Venus- and Mars-like atmospheres sharpens our focus on the scenarios still in play.”

The research’s co-authors additionally embody collaborators from the University of Arizona, Johns Hopkins University, University of Michigan, the Space Telescope Science Institute, and members of the JWST-TST DREAMS Team.

Improved observations

Exoplanet atmospheres are studied utilizing a way referred to as transmission spectroscopy. When a planet passes in entrance of its host star, the starlight is filtered via the planet’s ambiance. Astronomers can decide which molecules are current within the ambiance by seeing how the sunshine modifications at completely different wavelengths.

“Each molecule has a spectral fingerprint. You can compare your observations with those fingerprints to suss out which molecules may be present,” says Glidden.

JWST has a bigger wavelength protection and better spectral decision than its predecessor, the Hubble Space Telescope, which makes it doable to watch molecules like carbon dioxide and methane which are extra generally present in our personal photo voltaic system. However, the improved observations have additionally highlighted the issue of stellar contamination, the place modifications within the host star’s temperature as a result of issues like sunspots and photo voltaic flares make it troublesome to interpret information.

“Stellar activity strongly interferes with the planetary interpretation of the data because we can only observe a potential atmosphere through starlight,” says Glidden. “It is challenging to separate out which signals come from the star versus from the planet itself.”

Ruling out atmospheric situations

The researchers used a novel method to mitigate for stellar exercise and, in consequence, “any signal you can see varying visit-to-visit is most likely from the star, while anything that’s consistent between the visits is most likely the planet,” says Glidden.

The researchers had been then in a position to evaluate the outcomes to a number of completely different doable atmospheric eventualities. They discovered that carbon dioxide-rich atmospheres, like these of Mars and Venus, are unlikely, whereas a heat, nitrogen-rich ambiance just like Saturn’s moon Titan stays doable. The proof, nevertheless, is simply too weak to find out if any ambiance was current, not to mention detecting a particular sort of fuel. Additional, ongoing observations which are already within the works will assist to slender down the chances.

“With our initial observations, we have showcased the gains made with JWST. Our follow-up program will help us to further refine our understanding of one of our best habitable-zone planets,” says Glidden.