UV constraints for habitability around dMe stars

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

Congreso; 39th COSPAR Scientific Assembly 2012; 2012

Most programs searching for terrestrial extrasolar planets focuse on dwarf M stars, which are the most common stars of the main sequence. One of the reasons for this preference is that the liquid-water habitable zone (LW-HZ) is closer to these colder stars, and it would be therefore easier to detect a terrestrial planet inside it. However, there other conditions a planet must meet to be suitable for life. For example, it is believed that planets in the LW-HZ should be tidally locked, and therefore have a very hot face and a very cold one. However, recent atmospheric modeling provided evidences that heat could be transferred to the cold face. Additionally, are activity in many of these stars, in particular dMe stars, is a factor to be analyzed in order to determine if planets in the LW-HZ can be suitable for life, since the strong UV radiation emmited during these events could have a strong impact over potential life beings. In this work we analyze the capability of UV-resistant microorganisms which inhabit in hypersaline environments on Earth, such as halophilic archaea, to survive the strong UV radiation characteristic of are activity in dMe stars. Our results showed that haloarchaeal cells can survive at the tested doses, showing that this type of life could survive in this kind of hostile UV environments.