Habitable Zones & Global Climate

The Influence Of Tidal Heating On The Habitability Of Planets Orbiting White Dwarfs

By Keith Cowing

Status Report

astro-ph.EP

March 7, 2023

Filed under astro-ph.EP, exoplanet, habitability, tidal heating, white dwarf

The Influence Of Tidal Heating On The Habitability Of Planets Orbiting White Dwarfs — Evolution of the habitable zone (HZ) for planets around a white dwarf with contributions to total planetary heating (dashed) from tidal heating (blue) and incident stellar radiation (red). Each panel shows a different mode of evolution with a different selection of initial physical and orbital parameters. In the top panel, we show the evolution of an Earth-analog with initial semi-major axis of a = 0.2 and eccentricity of e = 0.7. This planet initially resides within the tidal habitable zone. The subsequent semi-major axis evolution caused by tidal circularization does not follow the location of the habitable zone at late times. In the bottom panel, we show the evolution of a TRAPPIST-1 e-analog with initial semi-major axis of a = 0.2 and eccentricity of e = 0.8. Its semi-major axis evolution traces the location of the habitable zone for the first 10 Gyr of the white dwarf phase. The physical parameters of each planet are presented in Table 1. — astro-ph.EP

In recent years, there have been a growing number of observations indicating the presence of rocky material in short-period orbits around white dwarfs. In this Letter, we revisit the prospects for habitability around these post-main-sequence star systems.

In addition to the typically considered radiative input luminosity, potentially habitable planets around white dwarfs are also subjected to significant tidal heating. The combination of these two heating sources can, for a narrow range of planetary properties and orbital parameters, continuously maintain surface temperatures amenable for habitability for planets around white dwarfs over time scales up to 10 Gyr.

We show that for a specific locus of orbital parameter space, tidal heating can substantially extend the timescale of continuous habitability for a planet around a white dwarf.

Juliette Becker, Darryl Z. Seligman, Fred C. Adams, Marshall J. Styczinski

Comments: Accepted to ApJL
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2303.02217 [astro-ph.EP] (or arXiv:2303.02217v1 [astro-ph.EP] for this version)
Submission history
From: Juliette Becker
[v1] Fri, 3 Mar 2023 21:22:10 UTC (1,532 KB)
https://arxiv.org/abs/2303.02217
Astrobiology

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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