NON-AXISYMMETRIC FLOWS ON HOT JUPITERS WITH OBLIQUE MAGNETIC FIELDS

Giant planets that reside in close proximity to their host stars are subject to extreme irradiation, which gives rise to thermal ionization of trace alkali metals in their atmospheres. On objects where the atmospheric electrical conductivity is substantial, the global circulation couples to the back...

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Veröffentlicht in:The Astrophysical journal Jg. 794; H. 1; S. 10 - 7
Hauptverfasser: Batygin, Konstantin, Stanley, Sabine
Format: Journal Article
Sprache:Englisch
Veröffentlicht: United States 10.10.2014
Schlagworte:
ALKALI METALS
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
Atmospherics
AXIAL SYMMETRY
Circulation
DIPOLES
ECLIPSE
ELECTRIC CONDUCTIVITY
Exact solutions
Extrasolar planets
FORECASTING
Ionization
IRRADIATION
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MATHEMATICAL SOLUTIONS
PLANETS
SATELLITE ATMOSPHERES
SATELLITES
STARS
Stellar atmospheres
WIND
ISSN:1538-4357, 0004-637X, 1538-4357
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Zusammenfassung:Giant planets that reside in close proximity to their host stars are subject to extreme irradiation, which gives rise to thermal ionization of trace alkali metals in their atmospheres. On objects where the atmospheric electrical conductivity is substantial, the global circulation couples to the background magnetic field, inducing supplementary fields and altering the nature of the flow. To date, a number of authors have considered the influence of a spin-pole aligned dipole magnetic field on the dynamical state of a weakly ionized atmosphere and found that magnetic breaking may lead to significantly slower winds than predicted within a purely hydrodynamical framework. Here, we consider the effect of a tilted dipole magnetic field on the circulation and demonstrate that in addition to regulating wind velocities, an oblique field generates stationary non-axisymmetric structures that adhere to the geometry of the magnetic pole. Using a kinematic perturbative approach, we derive a closed-form solution for the perturbed circulation and show that the fractional distortion of zonal jets scales as the product of the field obliquity and the Elsasser number. The results obtained herein suggest that on planets with oblique magnetic fields, advective shifts of day side hotspots may have substantial latitudinal components. This prediction may be tested observationally using the eclipse mapping technique.
Bibliographie:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1538-4357
0004-637X
1538-4357
DOI:10.1088/0004-637X/794/1/10