The Reflection Effect in Interacting Binaries or in Planet-Star Systems
Authors:
J. Budaj
Image & caption:
Please click on image thumbnail to get more info:
Image caption::
Schematic illustration of the reflection effect which consists of
reflection, heating, and heat redistribution. This is a pole-on view of the planet
irradiated by the star. Red regions on the day side are hot while yellow regions
on the night side and around poles are cool due to the irradiation and zonal
heat transfer. δ is irradiating angle, AB is Bond albedo, Pr is heat redistribution
parameter, Tir is temperature associated with local heating, Tdn is associated
with heat redistribution, and Told is associated with surface temperatures in the
absence of the irradiation. The Roche shape of the planet corresponds to the
filling factor equal to 1. The position and size of the star are not to scale.
Description:
A new model of the reflection effect was elaborated. Model describes the shape,
surface temperature distribution, lightcurves and spectra of a strongly irradiated stellar
or substellar object. Our model takes into account the reflection
(scattering), heating, and heat redistribution over the surface of the irradiated object,
limb and gravity darkening, orbital revolution and rotation of the exoplanet with appropriate Doppler shifts for the scattered and thermal radiation. Subsequently, the model was applied
to an extreme case of "interacting binaries" -extrasolar planets.
It was discovered that some of the 78 currently know transiting exoplanets have significant
departures from the spherical shape. It was found that HD189733b has a low Bond albedo and intense heat redistribution, while WASP-19b has a low Bond albedo and low heat redistribution.
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SAS
