Proxima Centauri b And Most Other Exo-Planets Are Likely Uninhabitable
http://www.forbes.com/...entauri-b-and-most-other-exo-planets-are-likely-uninhabitable/#77f9a9344218
Proxima Centauri b - the newly-discovered earth-mass planet once thought to be a real contender for habitability - is, in fact, very likely to be
uninhabitable, a new study concludes. And even if Proxima Centauri b - and the estimated tens of billions of other extrasolar planets like it -
did once have habitable atmospheres, astrobiologists now say extreme flaring from their parent stars likely would have eroded their atmospheres.
NASA says Proxima Centauri b, which orbits our nearest stellar neighbor Proxima Centauri at a distance some 20 times closer than Earth to the Sun, is
likely to have been subjected to torrents of X-ray and extreme ultraviolet (UV) radiation multiple times a day. That is, when its host star was younger
and even more magnetically-active than today.
In a paper just published in The Astrophysical Journal Letters, the authors note that earth-mass planets in close orbits around young, magnetically-active
low mass stars would be subject to much atmospheric havoc. In fact, within some ten million years the planet Proxima Centauri b, which lies only 4.2 light
years away in Centaurus, may have lost a trillion metric tons of its atmospheric oxygen to space. Or long before the planet could have developed microbial
life.