A test for the search for life on extrasolar planets - Looking for the terrestrial vegetation signature in the Earthshine spectrum

By L. Arnold, S. Gillet, O. Lardière, P. Riaud, J. S. O. D. H. P. O. Cnrs, L. -. Cnrs, O. Paris-meudon. 2002

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We report spectroscopic observations (400 to 800nm, R = approx 100) of Earthshine in June, July and October 2001 from which normalised 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 10 +/-3%) around 700nm has been measured in the Earth albedo. It is interpreted as being due to the vegetation red edge, expected to be between 2 to 10% of the Earth albedo at 700nm, depending on models. We discuss the primary goal of the present observations: their application to the detection of vegetation-like biosignatures on extrasolar planets.

Subfields: Astronomy and Astrophysics, Ecology, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/f057c615657bbad9b1876d06e65c81108d0ebe83

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Citations in the corpus

Earth system science related imaging spectroscopy — an assessment (2009, methodology): “…methods based on imaging spectroscopy are not exclusively applied in Earth observation, but also in space research (Clark et al., 2005), exobiology (Arnold et al., 2002; Kiang et al., 2007a,b), neurosciences (Devonshire et al., 2004), chemometrics (Fernández Pierna et al., 2004), amongst others…”
Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life (2017, background): “Des Marais et al. (2002) discussed the VRE as a surface biosignature of land vegetation, as it has been shown to be detectable in observations of Earth from the Galileo spacecraft (Sagan et al., 1993), as well as in the Earthshine spectrum of light reflected from the Moon (Arnold et al., 2002; Woolf”
Exoplanet Atmospheres: Physical Processes (2010, background): “Global, instantaneous spectra and photometry can be obtained from observations from Earth itself—by Earthshine measurements (Arnold et al. 2002; Woolf et al. 2002).”
Spectropolarimetric signatures of Earth-like extrasolar planets (2007, background): “…research groups (see e.g. Hamdani et al. 2006; Montañés-Rodrı́guez et al. 2006; Tinetti et al. 2006b,a; Seager et al. 2005; Woolf et al. 2002; Arnold et al. 2002) in spectra of Earthshine, the sunlight that has first been reflected by the Earth and then by the moon, and tht can be…”
Retrieval of foliar information about plant pigment systems from high resolution spectroscopy (2009, background): “Furthermore, the stability of chlorophyll molecules makes them a target, along with water, in the search for extraterrestrial life (Arnold et al., 2002; Wolstencroft and Raven, 2002; Seager et al., 2005).”