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Using Deep Space Climate Observatory Measurements to Study the Earth as an Exoplanet

Jiang, Jonathan H. and Zhai, Albert J. and Herman, Jay and Zhai, Chengxing and Hu, Renyu and Su, Hui and Natraj, Vijay and Li, Jiazheng and Xu, Feng and Yung, Yuk L. (2018) Using Deep Space Climate Observatory Measurements to Study the Earth as an Exoplanet. Astronomical Journal, 156 (1). Art. No. 26. ISSN 1538-3881. doi:10.3847/1538-3881/aac6e2.

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Even though it was not designed as an exoplanetary research mission, the Deep Space Climate Observatory (DSCOVR) has been opportunistically used for a novel experiment in which Earth serves as a proxy exoplanet. More than 2 yr of DSCOVR Earth images were employed to produce time series of multiwavelength, single-point light sources in order to extract information on planetary rotation, cloud patterns, surface type, and orbit around the Sun. In what follows, we assume that these properties of the Earth are unknown and instead attempt to derive them from first principles. These conclusions are then compared with known data about our planet. We also used the DSCOVR data to simulate phase-angle changes, as well as the minimum data collection rate needed to determine the rotation period of an exoplanet. This innovative method of using the time evolution of a multiwavelength, reflected single-point light source can be deployed for retrieving a range of intrinsic properties of an exoplanet around a distant star.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper ItemDISCOVR data
Jiang, Jonathan H.0000-0002-5929-8951
Herman, Jay0000-0002-9146-1632
Zhai, Chengxing0000-0002-0291-4522
Hu, Renyu0000-0003-2215-8485
Su, Hui0000-0003-1265-9702
Natraj, Vijay0000-0003-3154-9429
Xu, Feng0000-0001-5155-9478
Yung, Yuk L.0000-0002-4263-2562
Additional Information:© 2018. The American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2018 April 2; revised 2018 May 9; accepted 2018 May 12; published 2018 June 27. This work was partially support by the Exoplanet Science Initiative (ESI) at the Jet Propulsion Laboratory (JPL), California Institute of Technology (Caltech), under contract with NASA. We acknowledge the DSCOVR project science team for support. We thank Nicolas Cowan of McGill University for detailed and constructive comments. Anthony Davis and Gerard van Harten of JPL, Stuart Bartlett of Caltech, Sara Seager of the Massachusetts Institute of Technology, and Adam Showman of the University of Arizona also provided useful comments on the data calibration, analysis methodology, and exoplanet imaging techniques. Data and code availability: The DSCOVR data used for this study can be downloaded at The computer code used during the study is available on request from the authors.
Group:Astronomy Department
Funding AgencyGrant Number
Subject Keywords:Earth
Issue or Number:1
Record Number:CaltechAUTHORS:20190102-155140742
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Official Citation:Jonathan H. Jiang et al 2018 AJ 156 26
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92026
Deposited By: George Porter
Deposited On:03 Jan 2019 15:37
Last Modified:16 Nov 2021 03:46

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