2014 Annual Science Report
Pennsylvania State University Reporting | SEP 2013 – DEC 2014
Biosignatures in Ancient Rocks - Kasting Group
We have been working on two things: 1) the question of whether there are plausible “false positives” for life on extrasolar planets, i.e., high abiotic O2 and/or O3 levels that might be confused with evidence for photosynthesis, and 2) hydrodynamic escape of hydrogen from H2- or H2O-rich primitive atmospheres. We are developing a two-component model to describe this process. Old single-component models evidently do not obey the diffusion limit, so are are trying to remedy that.
We are close to writing a paper on the false positives project. We can reproduce the apparent false positives of other groups (Hu et al., 2012; Domagal-Goldman et al., 2014; Tian et al., 2014), but we can also show that these results are based on an unphysical choice of lower boundary conditions which would not be expected to occur on a real planet.
We also have been working on a variety of other astrobiology projects which are related to the project described here in different ways. See our list of publications for late 2013-2014.
PROJECT INVESTIGATORS:James Kasting
RELATED OBJECTIVES:Objective 1.1
Formation and evolution of habitable planets.
Earth's early biosphere.
Biosignatures to be sought in nearby planetary systems