Simulated photoevaporative mass loss from hot jupiters in 3D

Journal Article · Sat Aug 01 00:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/808/2/173· OSTI ID:22882513

Tripathi, Anjali; Murray-Clay, Ruth A. ^[1]; Kratter, Kaitlin M. ^[2]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Department of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

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{sub p}=2.14R{sub Jup} and mass M{sub p}=0.53M{sub 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 ∼2×10{sup 10} g s{sup −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 Lyα at Doppler-shifted velocities of up to ±50 km s{sup −1}. Our work provides a starting point for further 3D models that can be used to predict observable signatures of hot Jupiter mass loss.

• OSTI ID: 22882513
• Journal Information: Astrophysical Journal, Vol. 808, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
ASYMMETRY
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
DOPPLER EFFECT
HYDRODYNAMICS
HYDROGEN
INTERACTIONS
MASS TRANSFER
PHOTOIONIZATION
PLANETARY ATMOSPHERES
PLANETS
SATELLITE ATMOSPHERES
SATELLITES
SPECTRA
SPHERICAL CONFIGURATION
STARS
STEADY-STATE CONDITIONS
STELLAR WINDS