Detection of planetary transits of the star HD 209458 in the Hipparcos data set

T. Castellano, J. Jenkins, D. E. Trilling, L. Doyle, D. Koch

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


A search of the Hipparcos satellite photometry data for the star HD 209458 reveals evidence for a planetary transit signature consistent with the planetary properties reported by Henry et al. and Charbonneau et al. and allows further refinement of the planet's orbital period. The long time baseline (about 2926 days or 830 periods) from the best Hipparcos transit-like event to the latest transit reported by Henry et al. for the night of 1999 November 15 (UT) allows for an orbital period determination of 3.524736 days with an uncertainty of 0.000045 days (3.9 s). The transit events observed by Charbonneau et al. fall at the interim times expected to within the errors of this newly derived period. A series of statistical tests was performed to assess the likelihood of these events occurring by chance. This was crucial given the ill-conditioned problem presented by the sparse sampling of the light curve and the non-Gaussian distribution of the points. Monte Carlo simulations using bootstrap methods with the actual Hipparcos HD 209458 data set indicate that the transit-like signals of the depth observed would only be produced by chance in 21 out of 1 million trials. The transit durations and depths obtained from the Hipparcos data are also consistent with those determined by Charbonneau et al. and Henry et al. within the limitations of the sampling intervals and photometric precision of the Hipparcos data.

Original languageEnglish (US)
Pages (from-to)L51-L53
JournalAstrophysical Journal
Issue number1 PART 2
StatePublished - Mar 20 2000


  • Methods: data analysis
  • Planetary systems
  • Stars: individual (HD 209458)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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