BD-14 3065b (TOI-4987b): from giant planet to brown dwarf: evidence for deuterium burning in old age?

Abstract

The present study reports the confirmation of BD-14 3065b, a transiting planet/brown dwarf in a triple-star system, with a mass near the deuterium burning boundary. BD-14 3065b has the largest radius observed within the sample of giant planets and brown dwarfs around post-main-sequence stars. Its orbital period is 4.3 days, and it transits a subgiant F-type star with a mass of $M_{\star }=1.41\pm 0.05M_{\odot }$, a radius of $R_{\star }=2.35\pm 0.08R_{\odot }$, an effective temperature of $T_{\mathrm{eff}}=6935\pm 90$ K, and a metallicity of $-0.34\pm 0.05$ dex. By combining TESS photometry with high-resolution spectra acquired with the TRES and Pucheros+ spectrographs, we measured a mass of $M_p=12.37\pm 0.92M_J$ and a radius of $R_p=1.926\pm 0.094R_J$. Our discussion of potential processes that could be responsible for the inflated radius led us to conclude that deuterium burning is a plausible explanation resulting from the heating of BD-14 3065b's interior. Detection of the secondary eclipse with TESS photometry enables a precise determination of the eccentricity $e_p=0.066\pm 0.011$ and reveals BD-14 3065b has a brightness temperature of $3520\pm 130$ K. With its unique characteristics, BD-14 3065b presents an excellent opportunity to study its atmosphere through thermal emission spectroscopy.

23 pages, 22 figures, accepted for publication in Astronomy & Astrophysics

References in corpus (39)

• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Detection of Thermal Emission from an Extrasolar Planet
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• Tidal Evolution of Close-in Extra-Solar Planets
• The TESS Objects of Interest Catalog from the TESS Prime Mission
• Modern stellar spectroscopy caveats
• Inflating Hot Jupiters With Ohmic Dissipation
• Kepler Flares II: The Temporal Morphology of White-Light Flares on GJ 1243
• CERES: A Set of Automated Routines for Echelle Spectra
• PyTransit: Fast and Easy Exoplanet Transit Modelling in Python
• Heat transport in giant (exo)planets: a new perspective
• Early Release Science of the exoplanet WASP-39b with JWST NIRCam
• Exoplanet Reflected Light Spectroscopy with PICASO
• XO-3b: A Massive Planet in an Eccentric Orbit Transiting an F5V Star
• The Orbit of WASP-12b is Decaying
• A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b
• Re-Evaluating WASP-12b: Strong Emission at 2.315 micron, Deeper Occultations, and an Isothermal Atmosphere
• On the Inference of a Star's Inclination Angle from its Rotation Velocity and Projected Rotation Velocity
• Most Sub-Arcsecond Companions of Kepler Exoplanet Candidate Host Stars are Gravitationally Bound
• Climate of an Ultra hot Jupiter: Spectroscopic phase curve of WASP-18b with HST/WFC3
• Age Determination in Upper Scorpius with Eclipsing Binaries
• pyaneti II: A multidimensional Gaussian process approach to analysing spectroscopic time-series
• Five key exoplanet questions answered via the analysis of 25 hot Jupiter atmospheres in eclipse
• Signatures of unresolved binaries in stellar spectra: implications for spectral fitting
• Evidence of Three Mechanisms Explaining the Radius Anomaly of Hot Jupiters
• The Challenge of Wide-Field Transit Surveys: The Case of GSC 01944-02289
• Ohmic Dissipation in the Interiors of Hot Jupiters
• Assessing the Effect of Stellar Companions from High-Resolution Imaging of Kepler Objects of Interest
• Rotation Periods, Inclinations, and Obliquities of Cool Stars Hosting Directly Imaged Substellar Companions: Spin-Orbit Misalignments are Common
• Deuterium burning in objects forming via the core accretion scenario - Brown dwarfs or planets?
• SOAR TESS Survey. II: The impact of stellar companions on planetary populations
• SOPHIE velocimetry of Kepler transit candidates. XV. KOI-614b, KOI-206b, and KOI-680b: a massive warm Jupiter orbiting a G0 metallic dwarf and two highly inflated planets with a distant companion around evolved F-type stars
• The Possible Tidal Demise of Kepler's First Planetary System
• TOI-811b and TOI-852b: New transiting brown dwarfs with similar masses and very different radii and ages from the TESS mission
• CRIRES+ detection of CO emissions lines and temperature inversions on the dayside of WASP-18b and WASP-76b
• The TESS Grand Unified Hot Jupiter Survey. II. Twenty New Giant Planets
• Transit Timing Variation of XO-3b: Evidence for Tidal Evolution of Hot Jupiter with High Eccentricity
• Search for planets around stars with wide brown dwarfs
• Thermal Phase Curves of XO-3b: an Eccentric Hot Jupiter at the Deuterium Burning Limit

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