Friday, October 31, 2014

Competitive Spectroscopic Confirmation of KOI-1299b: a Warm Jupiter in a Very Eccentric Orbit Around a Red Giant

Ortiz et al



Planets around evolved stars exhibit different properties than those orbiting main-sequence stars. One of the most notable differences is the paucity of planets orbiting at short distance from giant stars (a less than 0.5 AU). Detecting these rare close-in planets can shed light on planetary system formation and evolution mechanisms.


We study the Kepler object KOI-1299, an evolved star ascending the red giant branch. We aim at confirming the planetary nature of the Jupiter-like transit signal recurring every ~52.5 days, and characterizing the orbital elements of the system.


We derive radial velocities from multi-epoch high-resolution spectra of KOI-1299 acquired with CAFE at the 2.2m telescope of Calar Alto Observatory and FIES at the 2.56m Nordic Optical Telescope of Roque de los Muchachos Observatory.


We confirm the planetary nature of the transiting object KOI-1299b. We find a planetary mass of Mp=5.86 +\- 0.05 Mjup and an eccentricity of e=0.479 +\- 0.004. With a semi-major axis of a=0.304 +\- 0.007 AU, KOI-1299b is the first bona-fide warm-Jupiter detected to transit a giant star. We also find a radial velocity linear trend of 0.44 +\- 0.04 m s−1 d−1, which suggests the presence of a third object in the system. Current models of planetary evolution in the post main-sequence phase predict that KOI-1299b will be most likely engulfed by its host star before the latter reaches the tip of the red giant branch.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.