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arXiv · 1908.04350

Earth as an Exoplanet: A Two-dimensional Alien Map

Siteng Fan·Cheng Li·Jia-Zheng Li·Stuart Bartlett·Jonathan H. Jiang·Vijay Natraj·David Crisp·Yuk L. Yung
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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.

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Siteng Fan, Cheng Li, Jia-Zheng Li, Stuart Bartlett, Jonathan H. Jiang, Vijay Natraj, David Crisp, Yuk L. Yung. 2019-08-12. Earth as an Exoplanet: A Two-dimensional Alien Map. https://doi.org/10.3847/2041-8213/ab3a49

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