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Earth as an Exoplanet: A Two-dimensional Alien Map

Fan, Siteng and Li, Cheng and Li, Jia-Zheng and Bartlett, Stuart and Jiang, Jonathan H. and Natraj, Vijay and Crisp, David and Yung, Yuk L. (2019) Earth as an Exoplanet: A Two-dimensional Alien Map. Astrophysical Journal Letters, 882 (1). Art. No. L1. ISSN 2041-8213. doi:10.3847/2041-8213/ab3a49.

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Resolving spatially varying exoplanet features from single-point light curves is essential for determining whether Earth-like worlds harbor geological features and/or climate systems that influence habitability. To evaluate the feasibility and requirements of this spatial-feature resolving problem, we present an analysis of multi-wavelength single-point light curves of Earth, where it plays the role of a proxy exoplanet. Here, ~10,000 Deep Space Climate Observatory/Earth Polychromatic Imaging Camera frames collected over a two-year period were integrated over the Earth's disk to yield a spectrally dependent point source and analyzed using singular value decomposition. We found that, between the two dominant principal components (PCs), the second PC contains surface-related features of the planet, while the first PC mainly includes cloud information. We present the first two-dimensional (2D) surface map of Earth reconstructed from light curve observations without any assumptions of its spectral properties. This study serves as a baseline for reconstructing the surface features of Earth-like exoplanets in the future.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Fan, Siteng0000-0002-3041-4680
Li, Cheng0000-0002-8280-3119
Bartlett, Stuart0000-0001-5680-476X
Jiang, Jonathan H.0000-0002-5929-8951
Natraj, Vijay0000-0003-3154-9429
Crisp, David0000-0002-4573-9998
Yung, Yuk L.0000-0002-4263-2562
Additional Information:© 2019 The American Astronomical Society. Received 2019 July 1; revised 2019 August 5; accepted 2019 August 12; published 2019 August 27. This work was partly supported by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Y.L.Y. and D.C. acknowledge support by the Virtual Planetary Laboratory at the University of Washington. We thank Lixiang Gu and Mimi Gerstell for proofreading the manuscript.
Group:Astronomy Department
Funding AgencyGrant Number
University of WashingtonUNSPECIFIED
Subject Keywords:Exoplanet astronomy ; Exoplanet atmospheres ; Exoplanet atmospheric variability ; Exoplanet detection methods ; Exoplanet surface characteristics ; Exoplanet surface composition ; Exoplanet surface variability ; Exoplanets ; Extrasolar rocky planets
Issue or Number:1
Record Number:CaltechAUTHORS:20190828-074526085
Persistent URL:
Official Citation:Siteng Fan et al 2019 ApJL 882 L1.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:98277
Deposited By: Tony Diaz
Deposited On:28 Aug 2019 16:20
Last Modified:16 Nov 2021 17:38

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