The Compositional Diversity of Low-Mass Exoplanets

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Small terrestrial planet

Low-mass planets have an extraordinarily diverse range of bulk compositions, from primarily rocky worlds to those with deep gaseous atmospheres.

As techniques for measuring the masses of exoplanets are advancing the field towards the terrestrial regime, from ultra-short orbital periods to Venus-like distances, we identify the bounds on planet compositions, where sizes and incident fluxes inform bulk planet properties. In some cases, measurement precisions of planet masses and sizes are approaching the theoretical uncertainties in planet models.

An emerging picture explains aspects of the diversity of low-mass planets although some problems remain; do extreme low density low-mass planets challenge models of atmospheric mass loss? Are planet sizes strictly separated by bulk composition? Why do some stellar characterizations differ between observational techniques?

As the TESS mission begins, low-mass exoplanets around the nearest stars will soon be discovered and characterized with unprecedented precision, permitting more detailed planetary modeling and atmospheric characterization of low mass exoplanets than ever before.

Daniel Jontof-Hutter
(Submitted on 11 Nov 2019)
Comments: 31 pages, 8 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Journal reference: Annual Review of Earth and Planetary Sciences, 2019, vol. 47, p.141-171
Cite as: arXiv:1911.04598 [astro-ph.EP] (or arXiv:1911.04598v1 [astro-ph.EP] for this version)
Bibliographic data
From: Daniel Jontof-Hutter
[v1] Mon, 11 Nov 2019 23:18:45 UTC (606 KB)]
https://arxiv.org/abs/1911.04598
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