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[135.16] Using the Rossiter Effect to Confirm Terrestrial Extrasolar Planets

W. F. Welsh, J. A. Orosz (San Diego State University), R. A. Wittenmyer (University of Texas at Austin)

We demonstrate that the "Rossiter Effect", an observed spectroscopic radial velocity anomaly that occurs during transit, can be used to confirm the presence of an Earth-analog extrasolar planet. The amplitude of the effect depends on the projected rotation velocity of the star, the ratio of planet-to-star radii, the orbital inclination, and the limb darkening. Despite the very small fractional area of the star occulted by the planet (roughly 8x10^-5), the large value of the stellar rotation velocity (V_rot sin i of several km/s) means the effect can be detected with current state-of-the-art spectrographs. For a Jupiter-size planet such as HD 209458b, the Rossiter effect is easily detected; for an Earth-size planet the effect is much smaller, a few tenths of a m/s, but still possible to observe. In fact, in the Earth-analog case, the amplitude of the Rossiter effect is larger than the reflex radial velocity amplitude of the star. We demonstrate the above via simulations of the Rossiter effect that include the dominant non-Poisson noise source, stellar oscillations.

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.