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Title: MAPPING CLOUDS AND TERRAIN OF EARTH-LIKE PLANETS FROM PHOTOMETRIC VARIABILITY: DEMONSTRATION WITH PLANETS IN FACE-ON ORBITS

Abstract

We develop an inversion technique of annual scattered light curves to sketch a two-dimensional albedo map of exoplanets in face-on orbits. As a test bed for future observations of extrasolar terrestrial planets, we apply this mapping technique to simulated light curves of a mock Earth-twin at a distance of 10 pc in a face-on circular orbit. A primary feature in recovered albedo maps traces the annual mean distribution of clouds. To extract information of other surface types, we attempt to reduce the cloud signal by taking the difference of two bands. We find that the inversion of reflectivity difference between 0.8-0.9 and 0.4-0.5 {mu}m bands roughly recovers the continental distribution, except for high latitude regions persistently covered with clouds and snow. The inversion of the reflectivity difference across the red edge (0.8-0.9 and 0.6-0.7 {mu}m) emphasizes the vegetation features near the equator. The planetary obliquity and equinox can be estimated simultaneously with the mapping under the presence of clouds. We conclude that the photometric variability of the scattered light will be a powerful means for exploring the habitat of a second Earth.

Authors:
 [1];  [2]
  1. Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397 (Japan)
  2. Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)
Publication Date:
OSTI Identifier:
21565417
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 739; Journal Issue: 2; Other Information: DOI: 10.1088/2041-8205/739/2/L62; Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALBEDO; CLOUDS; MAPPING; ORBITS; PHOTOMETRY; PLANETS; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Kawahara, Hajime, and Fujii, Yuka, E-mail: kawa_h@tmu.ac.jp. MAPPING CLOUDS AND TERRAIN OF EARTH-LIKE PLANETS FROM PHOTOMETRIC VARIABILITY: DEMONSTRATION WITH PLANETS IN FACE-ON ORBITS. United States: N. p., 2011. Web. doi:10.1088/2041-8205/739/2/L62.
Kawahara, Hajime, & Fujii, Yuka, E-mail: kawa_h@tmu.ac.jp. MAPPING CLOUDS AND TERRAIN OF EARTH-LIKE PLANETS FROM PHOTOMETRIC VARIABILITY: DEMONSTRATION WITH PLANETS IN FACE-ON ORBITS. United States. doi:10.1088/2041-8205/739/2/L62.
Kawahara, Hajime, and Fujii, Yuka, E-mail: kawa_h@tmu.ac.jp. Sat . "MAPPING CLOUDS AND TERRAIN OF EARTH-LIKE PLANETS FROM PHOTOMETRIC VARIABILITY: DEMONSTRATION WITH PLANETS IN FACE-ON ORBITS". United States. doi:10.1088/2041-8205/739/2/L62.
@article{osti_21565417,
title = {MAPPING CLOUDS AND TERRAIN OF EARTH-LIKE PLANETS FROM PHOTOMETRIC VARIABILITY: DEMONSTRATION WITH PLANETS IN FACE-ON ORBITS},
author = {Kawahara, Hajime and Fujii, Yuka, E-mail: kawa_h@tmu.ac.jp},
abstractNote = {We develop an inversion technique of annual scattered light curves to sketch a two-dimensional albedo map of exoplanets in face-on orbits. As a test bed for future observations of extrasolar terrestrial planets, we apply this mapping technique to simulated light curves of a mock Earth-twin at a distance of 10 pc in a face-on circular orbit. A primary feature in recovered albedo maps traces the annual mean distribution of clouds. To extract information of other surface types, we attempt to reduce the cloud signal by taking the difference of two bands. We find that the inversion of reflectivity difference between 0.8-0.9 and 0.4-0.5 {mu}m bands roughly recovers the continental distribution, except for high latitude regions persistently covered with clouds and snow. The inversion of the reflectivity difference across the red edge (0.8-0.9 and 0.6-0.7 {mu}m) emphasizes the vegetation features near the equator. The planetary obliquity and equinox can be estimated simultaneously with the mapping under the presence of clouds. We conclude that the photometric variability of the scattered light will be a powerful means for exploring the habitat of a second Earth.},
doi = {10.1088/2041-8205/739/2/L62},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 2,
volume = 739,
place = {United States},
year = {2011},
month = {10}
}