Mapping, Geodesy, Cartography

Mapping Exoplanets

By Keith Cowing
Status Report
December 27, 2023
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Mapping Exoplanets
Map of normalized intensity, Ip/I∗, for the planet Kepler-7b based on orbital phase variations measured by the Kepler mission (adapted from Demory et al. 2013). The intensity is interpreted as reflected light, and hence is proportional to albedo, Ag = (Ip/I∗)(a/R∗) 2 , and the bright region on the planet’s western hemisphere has an albedo of 0.64, suggestive of reflective clouds (Sudarsky et al. 2000; Roman and Rauscher 2017). A possible explanation for the cloud pattern is that particles condense on the planet’s cooler nightside, are advected to the dayside by eastward winds, and sublimate when the star is overhead (Heng and Demory 2013; Parmentier et al. 2016). — astro-ph.EP

The varied surfaces and atmospheres of planets make them interesting places to live, explore, and study from afar.

Unfortunately, the great distance to exoplanets makes it impossible to resolve their disk with current or near-term technology. It is still possible, however, to deduce spatial inhomogeneities in exoplanets provided that different regions are visible at different times — this can be due to rotation, orbital motion, and occultations by a star, planet, or moon.

Astronomers have so far constructed maps of thermal emission and albedo for short period giant exoplanets. These maps constrain atmospheric dynamics and cloud patterns in exotic atmospheres. In the future, exo-cartography could yield surface maps of terrestrial planets, hinting at the geophysical and geochemical processes that shape them.

Nicolas B. Cowan, Yuka Fujii

Comments: Updated chapter for Handbook of Exoplanets, eds. Deeg & Belmonte. 19 pages, including 6 figures and 5 pages of references
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1704.07832 [astro-ph.EP] (or arXiv:1704.07832v5 [astro-ph.EP] for this version)
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Submission history
From: Nicolas Cowan
[v1] Tue, 25 Apr 2017 18:00:02 UTC (6,090 KB)
[v2] Tue, 2 May 2017 19:35:28 UTC (5,327 KB)
[v3] Tue, 25 Jul 2017 22:29:51 UTC (5,320 KB)
[v4] Thu, 3 Sep 2020 19:39:30 UTC (5,634 KB)
[v5] Fri, 22 Dec 2023 19:57:40 UTC (5,412 KB)

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