2011/06/30 by David M. Kipping, David Kipping, Joel Hartman +39 · 39 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Eccentricity (behavior) #Exoplanet #Orbital eccentricity #Orbital period #Photometry (optics) #Physics #Planet #Residual #Stars #Stellar, planetary, and galactic studies #astro-ph.EP
paper · pdf · doi:10.1088/0004-6256/142/3/95
published in The Astronomical Journal 142(3), 95 (Institute of Physics) · 12 pages, 7 figures, 7 tables. Accepted in AJ. Minor changes over previous version
arxiv created 2011/07/07 · openalex publication_date 2011/08/16 · arxiv updated 2015/05/28 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/05
We report the discovery of HAT-P-31b, a transiting exoplanet orbiting the V = 11.660 dwarf star GSC 2099-00908. HAT-P-31b is the first planet discovered with the Hungarian-made Automated Telescope (HAT) without any follow-up photometry, demonstrating the feasibility of a new mode of operation for the HATNet project. The 2.17 M J , 1.1 R J planet has a period of P b = 5.0054 days and maintains an unusually high eccentricity of e b = 0.2450 ± 0.0045, determined through Keck, FIbr-fed Échelle Spectrograph, and Subaru high-precision radial velocities (RVs). Detailed modeling of the RVs indicates an additional quadratic residual trend in the data detected to very high confidence. We interpret this trend as a long-period outer companion, HAT-P-31c, of minimum mass 3.4 M J and period ⩾2.8 years. Since current RVs span less than half an orbital period, we are unable to determine the properties of HAT-P-31c to high confidence. However, dynamical simulations of two possible configurations show that orbital stability is to be expected. Further, if HAT-P-31c has non-zero eccentricity, our simulations show that the eccentricity of HAT-P-31b is actively driven by the presence of c, making HAT-P-31 a potentially intriguing dynamical laboratory.