Simulated Photoevaporative Mass Loss from Hot Jupiters in 3D

Abstract

Ionizing stellar photons heat the upper regions of planetary atmospheres, driving atmospheric mass loss. Gas escaping from several hot, hydrogen-rich planets has been detected using UV and X-ray transmission spectroscopy. Because these planets are tidally locked, and thus asymmetrically irradiated, escaping gas is unlikely to be spherically symmetric. In this paper, we focus on the effects of asymmetric heating on local outflow structure. We use the Athena code for hydrodynamics to produce 3D simulations of hot Jupiter mass loss that jointly model wind launching and stellar heating via photoionization. Our fiducial planet is an inflated, hot Jupiter with radius $R_p=2.14R_{\mathrm{Jup}}$ and mass $M_p=0.53M_{\mathrm{Jup}}$. We irradiate the initially neutral, atomic hydrogen atmosphere with 13.6 eV photons and compute the outflow's ionization structure. There are clear asymmetries in the atmospheric outflow, including a neutral shadow on the planet's nightside. Given an incident ionizing UV flux comparable to that of the Sun, we find a steady-state mass loss rate of ~$2\times 10^{10}$ g s${}^{-1}$. The total mass loss rate and the outflow substructure along the substellar ray show good agreement with earlier 1D models, for two different fluxes. Our 3D data cube can be used to generate the outflow's extinction spectrum during transit. As a proof of concept, we find absorption of stellar Lyman-alpha at Doppler-shifted velocities of up to $\pm 50$ km s${}^{-1}$. Our work provides a starting point for further 3D models that can be used to predict observable signatures of hot Jupiter mass loss.

16 pages, 15 figures, accepted for publication in ApJ. Replacement includes revised citations. Code is available for download and use from http://github.com/tripathi/Atmospheric-Athena

References in corpus (17)

• Athena: A New Code for Astrophysical MHD
• Atmospheric Escape from Hot Jupiters
• A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
• Lyman-$\alpha$ Transit Spectroscopy and the Neutral Hydrogen Tail of the Hot Neptune GJ436b
• Near-UV Absorption, Chromospheric Activity, and Star-Planet Interactions in the WASP-12 system
• Energetic neutral atoms as the explanation for the high velocity hydrogen around HD 209458b
• KOI-2700b - A Planet Candidate With Dusty Effluents on a 22-Hour Orbit
• Classification of magnetized star--planet interactions: bow shocks, tails, and inspiraling flows
• New observations of the extended hydrogen exosphere of the extrasolar planet HD209458b
• Magnetically controlled mass loss from extrasolar planets in close orbits
• Magnetohydronamic Evolution of HII Regions in Molecular Clouds: Simulation Methodology, Tests, and Uniform Media
• Magnetohydrodynamic Simulations of Hot Jupiter Upper Atmospheres
• Re-visit of HST FUV observations of hot-Jupiter system HD 209458: No Si III detection and the need for COS transit observations
• Spectral, Spatial, and Time properties of the hydrogen nebula around exoplanet HD209458b
• Transiting the Sun: The impact of stellar activity on X-ray and ultraviolet transits
• Optical transmission photometry of the highly inflated exoplanet WASP-17b
• Thermal escape from extrasolar giant planets

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