Most Earth-Like Planet Yet May Have Been Found Just 40 Light Years Away

One of the worlds in the TRAPPIST-1 system, a mere 40 light-years away, just might be clad in a life-supporting atmosphere," reports ScienceAlert. "In exciting new JWST observations, the Earth-sized exoplanet TRAPPIST-1e shows hints of a gaseous envelope similar to our own, one that could facilitate liquid water on the surface."Although the detection is ambiguous and needs extensive follow-up to find out what the deal is, it's the closest astronomers have come yet in their quest to find a second Earth... [T]he first step is finding exoplanets that are the right distance from their host star, occupying a zone where water neither freezes under extreme cold nor evaporates under extreme heat. Announced in 2016, the discovery of the TRAPPIST-1 system was immediately exciting for this reason. The red dwarf star hosts seven exoplanets that have a rocky composition (as opposed to gas or ice giants), several of which are bang in the star's habitable, liquid water zone... Red dwarf stars are also much more active than Sun-like stars, rampant with flare activity that, scientists have speculated, may have stripped any planetary atmospheres in the vicinity. Closer inspections of TRAPPIST-1d, one of the other worlds in the star's habitable zone, have turned up no trace of an atmosphere. But TRAPPIST-1e is a little more comfortably located, at a slightly greater distance from the star... [T]he spectrum is consistent with an atmosphere rich in molecular nitrogen, with trace amounts of carbon dioxide and methane. This is pretty tantalizing. Earth's atmosphere is roughly 78 percent molecular nitrogen. If the results can be validated, TRAPPIST-1e might just be the most Earth-like exoplanet discovered to date. That is not a small if, though. Luckily, more JWST observations are in the pipeline, and the researchers should be able to validate or rule out an atmosphere very soon. After analyzing four transits of TRAPPIST-1e across TRAPPIST-1, "We are seeing two possible explanations," says astrophysicist Ryan MacDonald of the University of St Andrews in the UK. "The most exciting possibility is that TRAPPIST-1e could have a so-called secondary atmosphere containing heavy gases like nitrogen. "But our initial observations cannot yet rule out a bare rock with no atmosphere..." Astrophysicist Ana Glidden of MIT led the second team interpreting the results, and says "We are really still in the early stages of learning what kind of amazing science we can do with Webb. It's incredible to measure the details of starlight around Earth-sized planets 40 light-years away and learn what it might be like there, if life could be possible there." "We're in a new age of exploration that's very exciting to be a part of."

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