HAT-P-32b and HAT-P-33b: Two Highly Inflated Hot Jupiters Transiting High-jitter Stars
Abstract
We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V = 11.289 late-F-early-G dwarf star GSC 3281-00800, with a period P = 2.150008 ± 0.000001 d. The stellar and planetary masses and radii depend on the eccentricity of the system, which is poorly constrained due to the high-velocity jitter (~80 m s-1). Assuming a circular orbit, the star has a mass of 1.16 ± 0.04 M ⊙ and radius of 1.22 ± 0.02 R ⊙, while the planet has a mass of 0.860 ± 0.164 M J and a radius of 1.789 ± 0.025 R J. The second planet, HAT-P-33b, orbits the bright V = 11.188 late-F dwarf star GSC 2461-00988, with a period P = 3.474474 ± 0.000001 d. As for HAT-P-32, the stellar and planetary masses and radii of HAT-P-33 depend on the eccentricity, which is poorly constrained due to the high jitter (~50 m s-1). In this case, spectral line bisector spans (BSs) are significantly anti-correlated with the radial velocity residuals, and we are able to use this correlation to reduce the residual rms to ~35 m s-1. We find that the star has a mass of 1.38 ± 0.04 M ⊙ and a radius of 1.64 ± 0.03 R ⊙ while the planet has a mass of 0.762 ± 0.101 M J and a radius of 1.686 ± 0.045 R J for an assumed circular orbit. Due to the large BS variations exhibited by both stars we rely on detailed modeling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date.
Based in part on observations obtained at the W. M. Keck Observatory, which is operated by the University of California and the California Institute of Technology. Keck time has been granted by NOAO (A285Hr, A146Hr, A201Hr, A289Hr), NASA (N128Hr, N145Hr, N049Hr, N018Hr, N167Hr, N029Hr), and the NOAO Gemini/Keck time-exchange program (G329Hr).- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2011
- DOI:
- 10.1088/0004-637X/742/1/59
- arXiv:
- arXiv:1106.1212
- Bibcode:
- 2011ApJ...742...59H
- Keywords:
-
- planetary systems;
- stars: individual: HAT-P-32 GSC 3281-00800 HAT-P-33 GSC 2461-00988;
- techniques: photometric;
- techniques: spectroscopic;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 21 pages, 13 figures, 10 tables, submitted to ApJ