Characterizing the Cool KOIs. II. The M Dwarf KOI-254 and Its Hot Jupiter
Abstract
We report the confirmation and characterization of a transiting gas giant planet orbiting the M dwarf KOI-254 every 2.455239 days, which was originally discovered by the Kepler mission. We use radial velocity measurements, adaptive optics imaging, and near-infrared spectroscopy to confirm the planetary nature of the transit events. KOI-254 b is the first hot Jupiter discovered around an M-type dwarf star. We also present a new model-independent method of using broadband photometry to estimate the mass and metallicity of an M dwarf without relying on a direct distance measurement. Included in this methodology is a new photometric metallicity calibration based on J - K colors. We use this technique to measure the physical properties of KOI-254 and its planet. We measure a planet mass of MP = 0.505 M Jup, radius RP = 0.96 R Jup, and semimajor axis a = 0.030 AU, based on our measured stellar mass M sstarf = 0.59 M ⊙ and radius R sstarf = 0.55 R ⊙. We also find that the host star is metal-rich, which is consistent with the sample of M-type stars known to harbor giant planets.
Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by Caltech, the University of California and NASA.- Publication:
-
The Astronomical Journal
- Pub Date:
- May 2012
- DOI:
- 10.1088/0004-6256/143/5/111
- arXiv:
- arXiv:1112.0017
- Bibcode:
- 2012AJ....143..111J
- Keywords:
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- planetary systems;
- techniques: photometric;
- techniques: radial velocities;
- techniques: spectroscopic;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- AJ accepted (in press)