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from the in-star-trek-every-planet-is-habitable dept.
Earlier this month, a team of astronomers from the University of Liège, Belgium, and NASA, using the TRAPPIST instrument at the ESO site in La Silla, Chile, discovered three exoplanets with temperatures similar to those of the Earth and Venus orbiting an ultra-cool M class dwarf star. M dwarves makes up approximately 75 percent of the stars in our galaxy, and this discovery greatly improves the potential for habitable exoplanets.
A recent study from the Imperial College of London, however, suggests that, whilst these planets orbit cooler and less luminous stars, they may still be too hot to be habitable for life as we know it. Dr James Owen, Hubble Fellow and lead author of the study states:
It was previously assumed that planets with masses similar to Earth would be habitable simply because they were in the 'habitable zone'. However, when you consider how these planets evolve over billions of years this assumption turns out not to be true.
The atmospheres of these exoplanets are estimated to make up rougly one percent of their planetary mass. By comparison, the mass of our atmosphere is roughly one millionth of the mass of our planet. This suggests an especially thick atmosphere which, given the resultant greenhouse effect, may render these exoplanets uninhabitable. Naturally, this problem is inherent of planets of Earth-like mass, or heavier; smaller planets, e.g. of Mars-like mass, may lose some of this atmospheric mass through evaporation, as we have observed in our own solar system. Further cataloging of the orbital systems of M class dwarf stars will identify these low mass exoplanets as candidates for the ongoing search for extra-solar life.
(Score: 3, Interesting) by khallow on Friday May 27 2016, @09:12AM
(Score: 2) by b0ru on Friday May 27 2016, @09:18AM
I'm inclined to agree that the stellar wind is likely a contributing factor, but the mass of the exoplanets themselves is also important. For example, the comparison of the Earth and Mars; Earth, whilst closer to the Sun, thus, more affected by the solar wind, has managed to maintain an atmosphere partially due to being more massive than Mars, whereas Mars has lost atmosphere through evaporation into space.
(Score: 5, Interesting) by jimshatt on Friday May 27 2016, @10:24AM
I don't know if it's possible to look for exoplanets with magnetic field (maybe look for iron in the star it's orbiting)?
(Score: 2) by b0ru on Friday May 27 2016, @10:28AM
Our atmosphere would likely have been blown away by solar wind if we didn't have this awesome magnetic field.
Absolutely; a magnetic field is certainly a contributing factor, also.
maybe look for iron in the star it's orbiting
That'd certainly be a good start.