Roche lobe effects on the atmospheric loss from "Hot Jupiters"

Тип публикации: статья из журнала

Год издания: 2007

Идентификатор DOI: 10.1051/0004-6361:20066929

Ключевые слова: hydrodynamics; atmospheric effects; stars : activity; planets and satellites : general, Atmospheric effects, Hydrodynamics, Planets and satellites: general, Stars: activity, Gravitational effects, Satellites, Stars, Tidal power, X rays, Atmospheric loss, Energy balance equation, Mass loss enhancement, Planets

Аннотация: Context. A study of the mass loss enhancement for very close "Hot Jupiters" due to the gravitational field of the host star is presented. Aims. The influence of the proximity to a planet of the Roche lobe boundary on the critical temperature for blow-off conditions for estimating the increase of the mass loss rate through hydrodynamic blow-off for close-in exoplanets is investigated. Methods. We consider the gravitational potential for a star and a planet along the line that joins their mass centers and the energy balance equation for an evaporating planetary atmosphere including the effect of the stellar tidal force on atmospheric escape. Results. By studying the effect of the Roche lobe on the atmospheric loss from short-periodic gas giants we derived reasonably accurate approximate formulas to estimate atmospheric loss enhancement due to the action of tidal forces on a "Hot Jupiter" and to calculate the critical temperature for the onset of "geometrical blow-off", which are valid for any physical values of the Roche lobe radial distance. Using these formulas, we found that the stellar tidal forces can enhance the hydrodynamic evaporation rate from TreS-1 and OGLE-TR-56b by about 2 fold, while for HD 209458b we found an enhancement of about 50%. For similar exoplanets which are closer to their host star than OGLE-TR-56b, the mass loss enhancement can be even larger. Moreover, we showed that the effect of the Roche lobe allows "Hot Jupiters" to reach blow-off conditions at temperatures which are less than expected due to the stellar X-ray and EUV heating.

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Издание

Журнал: ASTRONOMY & ASTROPHYSICS

Выпуск журнала: Vol. 472, Is. 1

Номера страниц: 329-334

ISSN журнала: 00046361

Место издания: LES ULIS CEDEX A

Издатель: EDP SCIENCES S A

Авторы

  • Erkaev N.V. (Siberian Federal University)
  • Kulikov Yu.N. (Polar Geophysical Institute,Russian Academy of Sciences)
  • Lammer H. (Space Research Institute,Austrian Academy of Sciences)
  • Langmayr D. (Space Research Institute,Austrian Academy of Sciences)
  • Biernat H.K. (Institute for Physics,University of Graz)
  • Selsis F. (CNRS,UMR 5574,Universite Lyon 1)
  • Jaritz G.F. (Institute for Physics,University of Graz)

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