Habitable Zones & Global Climate

Eccentricity Distribution Beyond the Snow Line and Implications for Planetary Habitability

By Keith Cowing
Status Report
February 7, 2024
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Eccentricity Distribution Beyond the Snow Line and Implications for Planetary Habitability
Distribution of eccentricities for all planets more massive than 0.3 MJ interior to the snow line (left panels) and exterior to the snow line (right panels). For the top two panels, both the shade and the size of the plotted data are logarithmically proportional to the planet mass, where dark green indicates a low mass and light green indicates a high mass. The bottom two panels show the histograms of the eccentricity data appearing in the top two panels. — astro-ph.EP

A fundamental question in the study of planetary system demographics is: how common is the solar system architecture?

The primary importance of this question lies in the potential of planetary systems to create habitable environments, and dissecting the various components of solar system evolution that contributed to a sustainable temperate surface for Earth.

One important factor in that respect is volatile delivery to the inner system and the dependence on giant planets beyond the snow line as scattering agents, particularly as such cold giant planets are relatively rare.

Here, we provide an investigation of the eccentricity distribution for giant planet populations both interior and exterior to their system snow lines. We show that the median eccentricity for cold giants is 0.23, compared with a far more circular orbital regime for inner planets. We further present the results of a dynamical simulation that explores the particle scattering potential for a Jupiter analog in comparison with a Jupiter whose eccentricity matches that of the median cold giant eccentricity.

These simulations demonstrate that the capacity for such an eccentric cold giant system to scatter volatiles interior to the snow line is significantly increased compared with the Jupiter analog case, resulting in a far greater volume of Earth-crossing volatiles. Thus, many of the known systems with cold giant planets may harbor water worlds interior to the snow line.

Eccentricity Distribution Beyond the Snow Line and Implications for Planetary Habitability
Stephen R. Kane, Robert A. Wittenmyer

Comments: 10 pages, 2 figures, accepted for publication in the Astrophysical Journal Letters
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2402.03441 [astro-ph.EP] (or arXiv:2402.03441v1 [astro-ph.EP] for this version)
Submission history
From: Stephen Kane
[v1] Mon, 5 Feb 2024 19:00:07 UTC (52 KB)


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