Detection of an extrasolar planet atmosphere

David Charbonneau, Timothy M. Brown, Robert W. Noyes, Ronald L. Gilliland

Research output: Contribution to journalArticle

768 Citations (Scopus)

Abstract

We report high-precision spectrophotometric observations of four planetary transits of HD 209458, in the region of the sodium resonance doublet at 589.3 nm. We find that the photometric dimming during transit in a bandpass centered on the sodium feature is deeper by (2.32 ± 0.57) × 10-4 relative to simultaneous observations of the transit in adjacent bands. We interpret this additional dimming as absorption from sodium in the planetary atmosphere, as recently predicted from several theoretical modeling efforts. Our model for a cloudless planetary atmosphere with a solar abundance of sodium in atomic form predicts more sodium absorption than we observe. There are several possibilities that may account for this reduced amplitude, including reaction of atomic sodium into molecular gases and/or condensates, photoionization of sodium by the stellar flux, a low primordial abundance of sodium, and the presence of clouds high in the atmosphere.

Original languageEnglish (US)
Pages (from-to)377-384
Number of pages8
JournalAstrophysical Journal
Volume568
Issue number1 I
DOIs
StatePublished - Mar 20 2002

Fingerprint

extrasolar planets
planet
sodium
atmospheres
atmosphere
transit
dimming
planetary atmosphere
planetary atmospheres
detection
molecular gases
condensate
condensates
photoionization
gas
modeling

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Charbonneau, D., Brown, T. M., Noyes, R. W., & Gilliland, R. L. (2002). Detection of an extrasolar planet atmosphere. Astrophysical Journal, 568(1 I), 377-384. https://doi.org/10.1086/338770
Charbonneau, David ; Brown, Timothy M. ; Noyes, Robert W. ; Gilliland, Ronald L. / Detection of an extrasolar planet atmosphere. In: Astrophysical Journal. 2002 ; Vol. 568, No. 1 I. pp. 377-384.
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Charbonneau, D, Brown, TM, Noyes, RW & Gilliland, RL 2002, 'Detection of an extrasolar planet atmosphere', Astrophysical Journal, vol. 568, no. 1 I, pp. 377-384. https://doi.org/10.1086/338770

Detection of an extrasolar planet atmosphere. / Charbonneau, David; Brown, Timothy M.; Noyes, Robert W.; Gilliland, Ronald L.

In: Astrophysical Journal, Vol. 568, No. 1 I, 20.03.2002, p. 377-384.

Research output: Contribution to journalArticle

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Charbonneau D, Brown TM, Noyes RW, Gilliland RL. Detection of an extrasolar planet atmosphere. Astrophysical Journal. 2002 Mar 20;568(1 I):377-384. https://doi.org/10.1086/338770