| Issue |
A&A
Volume 392, Number 1, September II 2002
|
|
|---|---|---|
| Page(s) | 231 - 237 | |
| Section | Stellar atmospheres | |
| DOI | https://doi.org/10.1051/0004-6361:20020933 | |
| Published online | 22 August 2002 | |
A test for the search for life on extrasolar planets*
Looking for the terrestrial vegetation signature in the Earthshine spectrum
1
Observatoire de Haute-Provence (OHP) CNRS, 04870 Saint-Michel-l'Observatoire, France
2
Laboratoire d'Interférométrie Stellaire et Exoplanétaire (LISE) CNRS, 04870 Saint-Michel-l'Observatoire, France e-mail: sgohp@obs-hp.fr; lardiere@obs-hp.fr; riaud@obs-hp.fr
3
Observatoire de Paris-Meudon, 92195 Meudon Cedex, France e-mail: Jean.Schneider@obspm.fr; Pierre.Riaud@obspm.fr
Corresponding author: L. Arnold, arnold@obs-hp.fr
Received:
24
December
2001
Accepted:
6
May
2002
We report spectroscopic observations (
nm,
) of Earthshine in June, July and October 2001 from
which normalized Earth albedo spectra have been derived. The
resulting spectra clearly show the blue colour of the Earth due to
Rayleigh diffusion in its atmosphere. They also show the
signatures of oxygen, ozone and water vapour. We tried to extract
from these spectra the signature of Earth vegetation. A variable
signal (4 to 
) around 700 nm has been measured in
the Earth albedo. It is interpreted as being due to the vegetation
red edge, expected to be between 2 to 
of the Earth albedo
at 700 nm, depending on models. We discuss the primary goal of
the present observations: their application to the detection of
vegetation-like biosignatures on extrasolar planets.
Key words: astrobiology / stars: planetary systems
© ESO, 2002
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