HAT-P-31b,c: A Transiting, Eccentric, Hot Jupiter and a Long-Period, Massive Third-Body

Abstract

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 HAT planet discovered without any follow-up photometry, demonstrating the feasibility of a new mode of operation for the HATNet project. The 2.17 Mj, 1.1Rj planet has a period P = 5.0054 days and maintains an unusually high eccentricity of e = 0.2450+/-0.0045, determined through Keck, FIES and Subaru high precision radial velocities. Detailed modeling of the radial velocities 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 3.4Mj 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.

12 pages, 7 figures, 7 tables. Accepted in AJ. Minor changes over previous version

References in corpus (11)

• DHP Framework: Digital Health Passports Using Blockchain -- Use case on international tourism during the COVID-19 pandemic
• Transit timing effects due to an exomoon
• HD147506b: A Super-Massive Planet in an Eccentric Orbit Transiting a Bright Star
• Long Term Evolution of Close Planets Including the Effects of Secular Interactions
• TASS Mark IV Photometric Survey of the Northern Sky
• HAT-P-3b: A heavy-element rich planet transiting a K dwarf star
• On the formation of terrestrial planets in hot-Jupiter systems
• Astrometry in Wide-field Surveys
• HAT-P-30b: A transiting hot Jupiter on a highly oblique orbit
• HAT-P-28b and HAT-P-29b: Two Sub-Jupiter Mass Transiting Planets
• Tools for discovering and characterizing extrasolar planets

Cited by in corpus (25)

• The GAPS Programme with HARPS-N@TNG XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets
• Friends of Hot Jupiters I: A Radial Velocity Search for Massive, Long-Period Companions to Close-In Gas Giant Planets
• The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux
• Friends of Hot Jupiters II: No Correspondence Between Hot-Jupiter Spin-Orbit Misalignment and the Incidence of Directly Imaged Stellar Companions
• Observational constraints on tidal effects using orbital eccentricities
• TESS Transit Timing of Hundreds of Hot Jupiters
• ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations
• HAT-P-65b and HAT-P-66b: Two Transiting Inflated Hot Jupiters and Observational Evidence for the Re-Inflation of Close-In Giant Planets
• KELT-8b: A highly inflated transiting hot Jupiter and a new technique for extracting high-precision radial velocities from noisy spectra
• Friends of Hot Jupiters III: An Infrared Spectroscopic Search for Low-Mass Stellar Companions
• Qatar-2: A K dwarf orbited by a transiting hot Jupiter and a more massive companion in an outer orbit
• The GAPS Programme with HARPS-N@TNG V. A comprehensive analysis of the XO-2 stellar and planetary systems
• HADES RV Programme with HARPS-N at TNG XV. Planetary occurrence rates around early-M dwarfs
• Revisiting the correlation between stellar activity and planetary surface gravity
• Exploring the realm of scaled Solar System analogs with HARPS
• The HADES RV Programme with HARPS-N@TNG VIII. Gl15A: A multiple wide planetary system sculpted by binary interaction
• Ephemeris refinement of 21 Hot Jupiter exoplanets with high timing uncertainties
• The Stellar Obliquity and the Long-period planet in the HAT-P-17 Exoplanetary System
• WASP-South hot Jupiters: WASP-178b, WASP-184b, WASP-185b & WASP-192b
• The CARMENES search for exoplanets around M dwarfs. A long-period planet around GJ 1151 measured with CARMENES and HARPS-N data
• K2-263b: A 50-day period sub-Neptune with a mass measurement using HARPS-N
• Post-Newtonian effects on some characteristic timescales of transiting exoplanets
• Confirmation and characterisation of three giant planets detected by TESS from the FIES/NOT and Tull/McDonald spectrographs
• TESS Timings of 31 Hot Jupiters with Ephemeris Uncertainties
• The GAPS Programme at TNG LXVIII. Characterization of the outer substellar companion around HD 72659 with a multi-technique approach