2001/01/01 by John K. Webb, Imma Wormleaton · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1071/as01037
published as Publ. Astron. Soc. Austr., 2001, 18, 252-258 · 14 pages, 6 figures, to appear in Publ. Astron. Soc. Austr
openalex publication_date 2001/01/01 · arxiv created 2001/10/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
Abstract Although the extra-solar planets discovered so far are of the giant, gaseous type, the increased sensitivity of future surveys will result in the discovery of lower mass planets. The detection of O 2 in the atmosphere of a rocky extra-solar planet would be a potential indicator of life. In this paper we address the specific issue of whether we would be able to detect the O 2 A-band absorption feature in the atmosphere of a planet similar to the Earth, if it were in orbit around a nearby star. Our method is empirical, in that we use observations of the Earth's O 2 A-band, with a simple geometric modification for a transiting extra-solar planet, allowing for limb-darkening of the host star. We simulate the spectrum of the host star with the superposed O 2 A-band absorption of the transiting planet, assuming a spectral resolution of ~8 kms −1 (typical of current echelle spectrographs), for a range of spectral signal-to-noise ratios. The main result is that in principle we may be able to detect the O 2 A-band of the transiting planet for host stars with radii R ≤ 0.3 R ʘ . However, using existing instrumentation and 8m telescopes, this requires target M-stars with m ( V ) ≈ 10 or brighter for integration times of ~10 hours or less. The number of such stars over the sky is small. Larger aperture telescopes and/or improved instrumentation efficiency would enable surveys of M-stars down to m ( V ) ≈ 13 and greatly improve the chances of discovering life elsewhere.