ANALYTIC DESCRIPTION OF THE ROSSITER-MCLAUGHLIN EFFECT FOR TRANSITING EXOPLANETS: CROSS-CORRELATION METHOD AND COMPARISON WITH SIMULATED DATA
- Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)
- National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
- Global Edge Institute, Tokyo Institute of Technology, 2-21-1 Ookayama, Meguro, Tokyo 152-8550 (Japan)
- Department of Astrophysics, California Institute of Technology, MC 249-17 Pasadena, CA 91125 (United States)
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 et al., 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 et al., 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.
- OSTI ID:
- 21392324
- Journal Information:
- Astrophysical Journal, Vol. 709, Issue 1; Other Information: DOI: 10.1088/0004-637X/709/1/458; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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