Discovery and Rossiter-McLaughlin Effect of Exoplanet Kepler-8b
Abstract
We report the discovery and the Rossiter-McLaughlin effect of Kepler-8b, a transiting planet identified by the NASA Kepler Mission. Kepler photometry and Keck-HIRES radial velocities yield the radius and mass of the planet around this F8IV subgiant host star. The planet has a radius RP = 1.419 RJ and a mass, MP = 0.60 MJ, yielding a density of 0.26 g cm^-3, among the lowest density planets known. The orbital period is P = 3.523 days and orbital semima jor axis is 0.0483+0.0006/-0.0012 AU. The star has a large rotational v sin i of 10.5 +/- 0.7 km s^-1 and is relatively faint (V = 13.89 mag), both properties deleterious to precise Doppler measurements. The velocities are indeed noisy, with scatter of 30 m s^-1, but exhibit a period and phase consistent with the planet implied by the photometry. We securely detect the Rossiter-McLaughlin effect, confirming the planet's existence and establishing its orbit as prograde. We measure an inclination between the projected planetary orbital axis and the projected stellar rotation axis of lambda = -26.9 +/- 4.6 deg, indicating a moderate inclination of the planetary orbit. Rossiter-McLaughlin measurements of a large sample of transiting planets from Kepler will provide a statistically robust measure of the true distribution of spin-orbit orientations for hot jupiters in general.
Keywords
Cite
@article{arxiv.1001.0416,
title = {Discovery and Rossiter-McLaughlin Effect of Exoplanet Kepler-8b},
author = {Jon M. Jenkins and William J. Borucki and David G. Koch and Geoffrey W. Marcy and William D. Cochran and Gibor Basri and Natalie M. Batalha and Lars A. Buchhave and Tim M. Brown and Douglas A. Caldwell and Edward W. Dunham and Michael Endl and Debra A. Fischer and Thomas N. Gautier and John C. Geary and Ronald L. Gilliland and Steve B. Howell and Howard Isaacson and John Asher Johnson and David W. Latham and Jack J. Lissauer and David G. Monet and Jason F. Rowe and Dimitar D. Sasselov and William F. Welsh and Andrew W. Howard and Phillip MacQueen and Hema Chandrasekaran and Joseph D. Twicken and Stephen T. Bryson and Elisa V. Quintana and Bruce D. Clarke and Jie Li and Christopher Allen and Peter Tenenbaum and Hayley Wu and Soren Meibom and Todd C. Klaus and Christopher K. Middour and Miles T. Cote and Sean McCauliff and Forrest R. Girouard and Jay P. Gunter and Bill Wohler and Jennifer R. Hall and Khadeejah Ibrahim and AKM Kamal Uddin and Michael S. Wu and Paresh A. Bhavsar and Jeffrey Van Cleve and David L. Pletcher and Jessie A. Dotson and Michael R. Haas},
journal= {arXiv preprint arXiv:1001.0416},
year = {2015}
}
Comments
26 pages, 8 figures, 2 tables; In preparation for submission to the Astrophysical Journal