Search for primitive life on a distant planet: relevance of 02 and 03 detections

Details Search for primitive life on a distant planet: relevance of 02 and 03 detections Search for primitive life on a distant planet: relevance of 02 and 03 detections

Sep 1993

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993a%26a...277..309l&link_type=abstract

Astronomy and Astrophysics, Vol. 277, p. 309 (1993)

Biology

51

Planetary Systems - Exobiology - Origin Of Life - Extra-Solar Planet - Exo Planet - Life In The Universe

Scientific paper

Considering the future importance of the search for evidence of primitive life on a distant planet, we have revisited some points of the O2 and O3 detection criteria.
The budget of free oxygen and organic carbon on Earth is studied. If one includes the organic carbon in sediments, it confirms that O2 is a very reactive gas whose massive presence in a telluric planet atmosphere implies continuous production. Its detection would be a strong indication for photosynthetic activity, provided the planet is not in a runaway greenhouse phase.
In principle, the direct detection of O2 could be possible in the visible flux of the planet at 760 nm (oxygen A-band) but it would be extremely difficult, considering the much larger flux from the star. The alternative search for the 9.7 m absorption of O3 may be easier as the contrast with the star is improved by three orders of magnitude. An atmospheric model confirms that the O3 column density is not a linear tracer of the atmospheric O2 content as was found in the pioneer work by Paetzold (1962). However, the detection of a substantial O3 absorption (τ >25%) would indicate, within the validity of this model, a O2 ground pressure larger than 10 mbar. The question is raised of whether this pressure is sufficient to indicate a photosynthetic origin of the oxygen. If the answer was positive, it would be an even more sensitive test of photosynthetic activity than the detection of the oxygen A-band. Further studies of these points are clearly needed before determining an observing strategy.

Affiliated with

Also associated with

No associations

Rating

Search for primitive life on a distant planet: relevance of 02 and 03 detections does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Search for primitive life on a distant planet: relevance of 02 and 03 detections, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Search for primitive life on a distant planet: relevance of 02 and 03 detections will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1559025