On the indirect detection of sodium in the atmosphere of the planetary companion to HD 209458

J. J. Fortney, D. Sudarsky, Ivan - Hubeny, C. S. Cooper, William B. Hubbard, A. Burrows, J. I. Lunine

Research output: Contribution to journalArticle

86 Citations (Scopus)

Abstract

Using a self-consistent atmosphere code, we construct a new model of the atmosphere of the transiting extrasolar giant planet HD 209458b to investigate the disparity between the observed strength of the sodium absorption feature at 589 nm and the predictions of previous models. For the atmospheric temperature-pressure profile we derive, silicate and iron clouds reside at a pressure of several millibars in the planet's atmosphere. These clouds have significant vertical extent and optical depth because of our slant viewing geometry and lead to increased absorption in bands directly adjacent to the sodium line core. Using a non-LTE sodium ionization model that includes photoionization by stellar UV flux, collisional processes with H2, and radiative recombination, we show that the ionization depth in the planet's atmosphere reaches ∼1/2 mbar at the day/night terminator. Ionization leads to a slight weakening of the sodium feature. We present our baseline model, including ionization and clouds, which falls near the observational error bars. The sensitivity of our conclusions to the derived atmospheric temperature-pressure profile is discussed.

Original languageEnglish (US)
Pages (from-to)615-622
Number of pages8
JournalAstrophysical Journal
Volume589
Issue number1 I
DOIs
StatePublished - May 20 2003

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ionization
sodium
planets
atmospheres
atmospheric temperature
planet
atmosphere
air temperature
radiative recombination
profiles
night
optical thickness
optical depth
recombination
photoionization
silicates
silicate
slopes
iron
geometry

Keywords

  • Planetary systems
  • Radiative transfer
  • Stars: individual (HD 209458)

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

On the indirect detection of sodium in the atmosphere of the planetary companion to HD 209458. / Fortney, J. J.; Sudarsky, D.; Hubeny, Ivan -; Cooper, C. S.; Hubbard, William B.; Burrows, A.; Lunine, J. I.

In: Astrophysical Journal, Vol. 589, No. 1 I, 20.05.2003, p. 615-622.

Research output: Contribution to journalArticle

Fortney, J. J. ; Sudarsky, D. ; Hubeny, Ivan - ; Cooper, C. S. ; Hubbard, William B. ; Burrows, A. ; Lunine, J. I. / On the indirect detection of sodium in the atmosphere of the planetary companion to HD 209458. In: Astrophysical Journal. 2003 ; Vol. 589, No. 1 I. pp. 615-622.
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AU - Cooper, C. S.

AU - Hubbard, William B.

AU - Burrows, A.

AU - Lunine, J. I.

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