IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
UV habitability and dM stars: an approach for evaluation of biological survival
Autor/es:
ABREVAYA, X. C.; CORTÓN, E.; MAUAS, P.J.D.
Lugar:
Rio de Janeiro, Brasil
Reunión:
Simposio; Solar and Stellar Variability: Impact on Earth and Planets, IAU Symposium 264; 2009
Institución organizadora:
International Astronomical Union
Resumen:
Dwarf M stars comprise about 75 percent of all stars in the galaxy. For
several years planets orbiting M stars have been discarded as suitable
places for development of life. This paradigm now has changed and
terrestrial-type planets within liquid-water habitable zones (LW-HZ)
around M stars are reconsidered as possible hosts for life as we know
it. Nevertheless, large amount of UV radiation is emitted during flares
by this stars, and it is uncertain how these events could affect
biological systems. In particular UV-C λ < 290nm) exhibits the
most damaging effects for living organisms. To analyze the hypothesis
that UV could set a limit for the development of extraterrestrial life,
we studied the effect of UV-C treatment on halophile archaea cultures.
Halophile archaea are extremophile organisms, they are exposed to
intense solar UV radiation in their natural environment so they are
generally regarded as relatively UV tolerant. Halophiles inhabits in
hipersaline environments as salt lakes but also have been found in
ancient salt deposits as halites and evaporites on Earth. Since
evaporites have been detected in Martian meteorites, these organisms are
proposed as plausible inhabitants of Mars-like planets. Our preliminary
results show that even after UV damage, the surviving cells were able to
resume growth with nearly normal kinetics.