Day and night side core cooling of a strongly irradiated giant planet
Date
2012
Authors
Budaj, Jan
Hubeny, I
Burrows, A
Journal Title
Journal ISSN
Volume Title
Publisher
Springer
Abstract
Context. The internal heat loss, or cooling, of a planet determines its structure and evolution. Aims. We study the effects of irradiation, metallicity of the atmosphere, heat redistribution, stratospheres, and the depth where the heat redistribution takes place on the atmospheric structure, the core entropy, and subsequently on the cooling of the interior of the planet. Methods. We address in a consistent fashion the coupling between the day and the night sides of a planet by means of model atmosphere calculations with heat redistribution. We assume that strong convection leads to the same entropy on the day and night sides and that gravity is the same on both hemispheres. Results. We argue that the core cooling rates from the two hemispheres of a strongly irradiated planet may not be the same and that the difference depends on several important parameters. If the day-night heat redistribution is very efficient or if it takes place at the large optical depth, then the day-side and the night-side cooling may be comparable. However, if the day-night heat transport is not efficient or if it takes place at a shallow optical depth then there can be a large difference between the day-and the night-side cooling and the night side will cool more efficiently. If stellar irradiation becomes stronger, e.g. owing to stellar evolution or migration, cooling from both the day and the night sides is reduced. Enhanced metallicity of the atmosphere would act as an added "blanket" and reduces both the day-and the night-side cooling. However, a stratosphere on the planetary day side can enhance day-side cooling since its opacity acts as a "sunshade" that screens the stellar irradiation. These effects may also influence the well-known gravity darkening and bolometric albedo effects in interacting binaries, especially for strongly irradiated cold components.
Description
Keywords
Citation
Collections
Source
Astronomy and Astrophysics
Type
Journal article
Book Title
Entity type
Access Statement
License Rights
Restricted until
2037-12-31
Downloads
File
Description