Using biogenic sulfur gases as remotely detectable biosignatures on anoxic planets

Shawn D. Domagal-Goldman, Victoria S. Meadows, Mark W. Claire, James F. Kasting

Research output: Contribution to journalArticlepeer-review

85 Scopus citations

Abstract

We used one-dimensional photochemical and radiative transfer models to study the potential of organic sulfur compounds (CS2, OCS, CH3SH, CH3SCH3, and CH3S2CH3) to act as remotely detectable biosignatures in anoxic exoplanetary atmospheres. Concentrations of organic sulfur gases were predicted for various biogenic sulfur fluxes into anoxic atmospheres and were found to increase with decreasing UV fluxes. Dimethyl sulfide (CH3SCH3, or DMS) and dimethyl disulfide (CH3S2CH3, or DMDS) concentrations could increase to remotely detectable levels, but only in cases of extremely low UV fluxes, which may occur in the habitable zone of an inactive M dwarf. The most detectable feature of organic sulfur gases is an indirect one that results from an increase in ethane (C2H6) over that which would be predicted based on the planet's methane (CH4) concentration. Thus, a characterization mission could detect these organic sulfur gases and therefore the life that produces them if it could sufficiently quantify the ethane and methane in the exoplanet's atmosphere.

Original languageEnglish (US)
Pages (from-to)419-441
Number of pages23
JournalAstrobiology
Volume11
Issue number5
DOIs
StatePublished - Jun 1 2011

All Science Journal Classification (ASJC) codes

  • Agricultural and Biological Sciences (miscellaneous)
  • Space and Planetary Science

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