2022A&A...658L...7K


Query : 2022A&A...658L...7K

2022A&A...658L...7K - Astronomy and Astrophysics, volume 658, L7-7 (2022/2-1)

Shallowness of circulation in hot Jupiters. Advancing the Ohmic dissipation model.

KNIERIM H., BATYGIN K. and BITSCH B.

Abstract (from CDS):

The inflated radii of giant short-period extrasolar planets collectively indicate that the interiors of hot Jupiters are heated by some anomalous energy dissipation mechanism. Although a variety of physical processes have been proposed to explain this heating, recent statistical evidence points to the confirmation of explicit predictions of the Ohmic dissipation theory, elevating this mechanism as the most promising candidate for resolving the radius inflation problem. In this work, we present an analytic model for the dissipation rate and derive a simple scaling law that links the magnitude of energy dissipation to the thickness of the atmospheric weather layer. From this relation, we find that the penetration depth influences the Ohmic dissipation rate by an order of magnitude. We further investigate the weather layer depth of hot Jupiters from the extent of their inflation and show that, depending on the magnetic field strength, hot Jupiter radii can be maintained even if the circulation layer is relatively shallow. Additionally, we explore the evolution of zonal wind velocities with equilibrium temperature by matching our analytic model to statistically expected dissipation rates. From this analysis, we deduce that the wind speed scales approximately as 1/sqrt{(Teq-T0)}, where T0 is a constant that equals T0 ∼ 1000 K - 1800 K depending on planet-specific parameters (radius, mass, etc.). This work outlines inter-related constraints on the atmospheric flow and the magnetic field of hot Jupiters and provides a foundation for future work on the Ohmic heating mechanism.

Abstract Copyright: © H. Knierim et al. 2022

Journal keyword(s): magnetohydrodynamics (MHD) - planets and satellites: atmospheres - planets and satellites: magnetic fields - planets and satellites: interiors - planets and satellites: gaseous planets

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 BD+01 316b Pl 01 46 31.8576707085 +02 42 02.033178181           ~ 135 0
2 HD 15082b Pl 02 26 51.0582746497 +37 33 01.737746137           ~ 288 1
3 HD 189733b Pl 20 00 43.7130382888 +22 42 39.071811263           ~ 1293 1
4 HD 209458b Pl 22 03 10.7729598762 +18 53 03.548248479           ~ 1709 1

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2022.10.05-15:29:54

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