Review on habitability and biomarkers

L. Kaltenegger, M. Fridlund, J. Kasting

Research output: Contribution to journalConference articlepeer-review

10 Scopus citations


The detection of O2 or its product O3 is our most reliable biomarker so far. The existence of H2O in liquid state on the surface of a planet is considered essential for the development of life; even so, it is not a bioindicator. CO2 indicates an atmosphere, and abundant CH4 can indicate biological sources, although depending on the degree of oxidation of a planet's crust and upper mantle non-biological sources could also produce large amounts of CH4. In the thermal part of the spectrum, the shape gives a measure of the temperature of the object examined. The mid-IR spectra can determine the planet's albedo, the temperature of the observable emitting regions and thus the planet's size. Visible to near-IR spectra offer higher spatial resolution for the same collecting area, are minimally affected by temperature and therefore able to determine the abundance of atmospheric species. However the visible/near-IR continuum does not give direct indication of the planet size because of the possible albedo range.

Original languageEnglish (US)
Pages (from-to)277-282
Number of pages6
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number514
StatePublished - Oct 2002
EventProceedings of the 36th ESLAB Symposium; Earth-Like Planets and Moons - Noordwijk, Netherlands
Duration: Jun 3 2002Jun 8 2002

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Space and Planetary Science


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