2010/01/04 by Jon M. Jenkins, William J. Borucki, W. J. Borucki +67 · 1 citation
Chemistry · Materials Science · Physics and Astronomy · #Free Radicals and Antioxidants #Laser-Matter Interactions and Applications #Nonlinear Optical Materials Research #astro-ph.EP
paper · pdf · doi:10.1088/0004-637x/724/2/1108
26 pages, 8 figures, 2 tables; In preparation for submission to the Astrophysical Journal
arxiv created 2010/01/04 · arxiv updated 2015/05/14
We report on the discovery and the Rossiter–McLaughlin (R-M) 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 R P = 1.419 R J and a mass M P = 0.60 M J , yielding a density of 0.26 g cm −3 , one of the lowest planetary densities known. The orbital period is P = 3.523 days and the orbital semimajor 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 are deleterious to precise Doppler measurements. The velocities are indeed noisy, with scatter of 30 m s −1 , but exhibit a period and phase that are consistent with those implied by transit photometry. We securely detect the R-M 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 λ = −26 4 ± 10 1, indicating a significant inclination of the planetary orbit. R-M 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 around F and early G stars.