Cool Stars 14 - Submitted Abstract # 379
This version created on 06 October 2006

The UV Habitable Zone Around the M Star Gl 581


Andrea Buccino
Guillermo A. Lemarchand
Pablo Mauas

Nearly the 70% of Milky Way Galaxy are dM stars. Even they are low mass stars, 
they represent almost the 20% of luminous mass in our galaxy.  Due to their 
faint intrinsic luminosity, only those M stars that are within the solar 
neighborhood are possible to be observed. The last surveys of exoplanets has 
reported very few M stars with planetary systems and only one of them: Gl 581 
has been observed by IUE satellite. 

Ultraviolet radiation is known to inhibit photosynthesis, induce DNA destruction 
and cause damage to a wide variety of proteins and lipids. In particular, UV 
radiation between 200 and 300 nm becomes energetically very damaging to most of 
the terrestrial biological systems. On the other hand, UV radiation is usually 
considered one of the most important energy source on the primitive Earth for 
the synthesis of many biochemical compounds and, therefore, essential for 
several biogenesis processes. 

In this work we apply our model of UV Habitable Zone (Buccino et al., Icarus, 
183 (2006) 491-503) to study the UV constraints for the origin and the developmen
of life on a hypothetical terrestrial planet around Gl 581. We compared these 
results with the traditional HZ analyses.

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