Earth as an Exoplanet: A Two-dimensional Alien Map. (arXiv:1908.04350v1 [astro-ph.EP])

Earth as an Exoplanet: A Two-dimensional Alien Map. (arXiv:1908.04350v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Fan_S/0/1/0/all/0/1">Siteng Fan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_C/0/1/0/all/0/1">Cheng Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_J/0/1/0/all/0/1">Jia-Zheng Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bartlett_S/0/1/0/all/0/1">Stuart Bartlett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jiang_J/0/1/0/all/0/1">Jonathan H. Jiang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Natraj_V/0/1/0/all/0/1">Vijay Natraj</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crisp_D/0/1/0/all/0/1">David Crisp</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yung_Y/0/1/0/all/0/1">Yuk L. Yung</a>

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.

http://arxiv.org/icons/sfx.gif