Habitability TRAPPIST-1f

artist s impression of surface of trappist-1f, depicting liquid water ocean on surface. parent star , neighbouring planets illustrated.

the exoplanet announced either orbiting within or outside of habitable zone of parent star, region where, correct conditions , atmospheric properties, liquid water may exist on surface of planet. on 31 august 2017, astronomers @ hubble space telescope reported first evidence of possible water content on trappist-1 exoplanets.

trappist-1f has radius same earth, @ around 1.045 r⊕, 2 thirds of earth s mass, @ around 0.68 m⊕. so, considered unlikely rocky planet, , extremely unlikely earth-like one, rocky large iron core without thick hydrogen-helium atmosphere enveloping planet. simulations suggest planet approximately 20% water composition. such massive water envelope, pressure , temperature high enough keep water in gaseous state , liquid water exist clouds near top of trappist-1f’s atmosphere. trappist-1f therefore no more habitable other gas or ice-giant water clouds in atmosphere.

its host star red ultracool dwarf, 8% of mass of sun (close boundary between brown dwarfs , hydrogen-fusing stars). result, stars trappist-1 have ability live 4–5 trillion years, 400–500 times longer sun live. because of ability live long periods of time, trappist-1 1 of last remaining stars when universe older now, when gas needed form new stars exhausted, , remaining ones begin die off.

the planet tidally locked, 1 hemisphere permanently facing towards star, while opposite side shrouded in eternal darkness. however, between these 2 intense areas, there sliver of habitability – called terminator line, temperatures may suitable (about 273 k or 0 °c or 32 °f) liquid water exist. additionally, larger portion of planet may habitable if supports thick enough atmosphere transfer heat side facing away star.