The TRAPPIST-1 system hosts seven terrestrial-sized planets, in and around the habitable zone of their small M dwarf host star. Since M dwarf stars exhibit a long superluminous pre-main-sequence phase during which its planets likely experience extreme volatile loss, the TRAPPIST-1 planets may have highly evolved, possibly uninhabitable atmospheres. Resultant possible atmospheres may be post runaway atmospheres like Venus, dominated by CO2, or be dominated by O2 as a result of severe water loss. These atmospheres exhibit spectroscopic signals in transit that may be observable by the upcoming James Webb Space Telescope. For more, read this new paper led by Andrew Lincowski, Ph.D. Candidate in Astronomy and Astrobiology.