Improved modeling of the Rossiter-McLaughlin effect for transiting exoplanets
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Author(s)
Hirano, Teruyuki
Suto, Yasushi
Winn, Joshua Nathan
Taruya, Atshushi
Narita, Norio
Albrecht, Simon H.
Sato, Bunei
Date Issued
November 2011
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Hirano, Teruyuki et al. “IMPROVED MODELING OF THE ROSSITER-McLAUGHLIN EFFECT FOR TRANSITING EXOPLANETS.” The Astrophysical Journal 742.2 (2011): 69.
Version
Author's final manuscript
Abstract
We present an improved formula for the anomalous radial velocity of the star during planetary transits due to the Rossiter-McLaughlin (RM) effect. The improvement comes from a more realistic description of the stellar absorption line profiles, taking into account stellar rotation, macroturbulence, thermal broadening, pressure broadening, and instrumental broadening. Although the formula is derived for the case in which radial velocities are measured by cross-correlation, we show through numerical simulations that the formula accurately describes the cases where the radial velocities are measured with the iodine absorption-cell technique. The formula relies on prior knowledge of the parameters describing macroturbulence, instrumental broadening, and other broadening mechanisms, but even 30% errors in those parameters do not significantly change the results in typical circumstances. We show that the new analytic formula agrees with previous ones that had been computed on a case-by-case basis via numerical simulations. Finally, as one application of the new formula, we reassess the impact of the differential rotation on the RM velocity anomaly. We show that differential rotation of a rapidly rotating star may have a significant impact on future RM observations.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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Creative Commons Attribution-Noncommercial-Share Alike 3.0
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DOI of Published Version
https://doi.org/10.1088/0004-637x/742/2/69
