Limits of photosynthesis in extrasolar planetary systems for earth-like planets.
We present a general modeling scheme for investigating the possibility of photosynthesis-based life on extrasolar planets. The scheme focuses on the identification of the habitable zone in main-sequence-star planetary systems with planets of Earth mass and size. Our definition of habitability is based on the long-term possibility of photosynthetic biomass production as a function of mean planetary surface temperature and atmospheric CO2-content. All the astrophysical, climatological, biogeochemical, and geodynamic key processes involved in the generation of photosynthesis-driven life conditions are taken into account. Implicitly, a co-genetic origin of the central star and the orbiting planet is assumed. The numerical solution of an advanced geodynamic model yields realistic look-up diagrams for determining the limits of photosynthesis in extrasolar planetary systems, assuming minimum CO2 levels set by the demand of C4 photosynthesis.
Franck
S
S
Potsdam Institute for Climate Impact Research, PF 601203, 14412 Potsdam, Germany.
von Bloh
W
W
Bounama
C
C
Steffen
M
M
Schonberner
D
D
Schellnhuber
H J
HJ
D001272:Atmosphere / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002245:Carbon Dioxide / Q000032:analysis*; D018559:Exobiology; D005118:Extraterrestrial Environment; D055593:Geological Phenomena; D005844:Geology; D008956:Models, Chemical; D010788:Photosynthesis; D016083:Planets; D014887:Weather
D002245:Carbon Dioxide; D002244:Carbon