EV-Lac as a potential host for habitable planets

ABREVAYA, X.C.; CORTÓN, E.; MAUAS, P.J.D.

Mendoza

Simposio; IAUS 286: Comparative magnetic minima: characterizing quiet times in the Sun and stars; 2011

International Astronomical Union

At present, dwarf M stars are being considered as potential hosts for habitable planets. However, an important fraction of these stars are are stars, which among other things emit large amounts of UV radiation during ares, and it is unknown how this radiation can affect life, since biological systems are particularly vulnerable to UV. In this work we evaluate a well known dMe star, EV Lacertae (GJ 873) as a potential site for the emergence and evolution of life, focusing on the effects of the UV emission associated with flare activity. Since UV-C (wavelenghts < 290 nm) is particularly harmful for living organisms, we studied the efect of UV-C radiation on halophile archaea cultures. The halophilic archaea or haloarchaea are extremophile microorganisms, which inhabit in hypersaline environments and show several mechanisms to cope with UV radiation since they are naturally exposed to intense solar UV radiation on Earth. To select the irradiance to be tested we considered a moderate are of this star. We obtained the mean value for the UV-C irradiance integrating the IAU spectrum in the impulsive phase, and considering a hypothetical planet in the center of the liquid water habitability zone. To select the irradiation times we took the most frequent duration of flares on this star which is from 10 to 30 minutes. Our results show that even after considerable UV damage, the haloarchaea cells survive at the tested doses, showing that this kind of life could survive in a relatively hostile UV environment.