Earth as an Exoplanet: A Two-dimensional Alien Map
Abstract
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 DSCOVR/EPIC 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.
Keywords
Cite
@article{arxiv.1908.04350,
title = {Earth as an Exoplanet: A Two-dimensional Alien Map},
author = {Siteng Fan and Cheng Li and Jia-Zheng Li and Stuart Bartlett and Jonathan H. Jiang and Vijay Natraj and David Crisp and Yuk L. Yung},
journal= {arXiv preprint arXiv:1908.04350},
year = {2019}
}
Comments
Accepted by ApJL, 7 pages, 4 figures