Analytic description of the rossiter-mclaughlin effect for transiting exoplanets: Cross-correlation method and comparison with simulated data

Teruyuki Hirano, Yasushi Suto, Atsushi Taruya, Norio Narita, Bun'Ei Sato, John Asher Johnson, Joshua N. Winn

Research output: Contribution to journalArticle

48 Scopus citations

Abstract

We obtain analytical expressions for the velocity anomaly due to the Rossiter-McLaughlin (RM) effect, for the case when the anomalous radial velocity is obtained by cross-correlation with a stellar template spectrum. In the limit of vanishing width of the stellar absorption lines, our result reduces to the formula derived by Ohta etal., which is based on the first moment of distorted stellar lines. Our new formula contains a term dependent on the stellar line width, which becomes important when rotational line broadening is appreciable. We generate mock transit spectra for four existing exoplanetary systems (HD 17156, TrES-2, TrES-4, and HD 209458) following the procedure of Winn etal., and find that the new formula is in better agreement with the velocity anomaly extracted from the mock data. Thus, our result provides a more reliable analytical description of the velocity anomaly due to the RM effect, and explains the previously observed dependence of the velocity anomaly on the stellar rotation velocity.

Original languageEnglish (US)
Pages (from-to)458-469
Number of pages12
JournalAstrophysical Journal
Volume709
Issue number1
DOIs
StatePublished - 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Planetary systems
  • Planets and satellites: formation
  • Stars: rotation
  • Techniques: radial velocities
  • Techniques: spectroscopic

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