Colors of a second earth: Estimating the fractional areas of ocean, land, and vegetation of earth-like exoplanets

Yuka Fujii, Hajime Kawahara, Yasushi Suto, Atsushi Taruya, Satoru Fukuda, Teruyuki Nakajima, Edwin L. Turner

Research output: Contribution to journalArticle

50 Scopus citations

Abstract

Characterizing the surfaces of rocky exoplanets via their scattered light will be an essential challenge in investigating their habitability and the possible existence of life on their surfaces. We present a reconstruction method for fractional areas of different surface types from the colors of an Earth-like exoplanet. We create mock light curves for Earth without clouds using empirical data. These light curves are fitted to an isotropic scattering model consisting of four surface types: ocean, soil, snow, and vegetation. In an idealized situation where the photometric errors are only photon shot noise, we are able to reproduce the fractional areas of those components fairly well. The results offer some hope for detection of vegetation via the distinct spectral feature of photosynthesis on Earth, known as the red edge. In our reconstruction method, Rayleigh scattering due to the atmosphere plays an important role, and for terrestrial exoplanets with an atmosphere similar to our Earth, it is possible to estimate the presence of oceans and an atmosphere simultaneously.

Original languageEnglish (US)
Pages (from-to)866-880
Number of pages15
JournalAstrophysical Journal
Volume715
Issue number2
DOIs
StatePublished - Jan 1 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Astrobiology
  • Earth
  • Scattering
  • Techniques: photometric

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