TOI-6884b: A low-mass brown dwarf transiting a slightly evolved star

Abstract

We report the discovery of a low-mass transiting brown dwarf orbiting TOI-6884 (TIC~156514476, $T_{\mathrm{mag}}=11.4$) from NASA's \textit{Transiting Exoplanet Survey Satellite} (\textit{TESS}) mission. The \textit{TESS} light curves initially suggested an orbital period of $\sim$14.42~days; however, our high-precision ground-based radial velocity measurements and multi-epoch time-series photometry reveal this to be a harmonic alias. We determine the true orbital period to be $4.808264_{-0.000014}^{+0.000015}$~days and confirm the substellar nature of the companion. TOI-6884b has a mass of $26.32_{-0.93}^{+0.98}{M}_{\mathrm{J}}$, a radius of $0.927_{-0.52}^{+0.51}{R}_{\mathrm{J}}$, and resides on a nearly circular orbit ($e=0.067_{-0.012}^{+0.010}$). Its host star is a late F-type slightly evolved star with $M_{\star }=1.410_{-0.069}^{+0.075}{M}_{\odot }$,\msun, $R_{\star }=1.840_{-0.073}^{+0.072}{R}_{\odot }$, $\log g=4.057_{-0.039}^{+0.045}$, $[Fe/H]=0.094_{-0.068}^{+0.073}$~dex, and $T_{\mathrm{eff}}=6330_{-160}^{+180}$,\mathrm{K}$. TOI-6884b is a key addition to the small population of well-characterized transiting brown dwarfs orbiting host stars that have evolved off the main sequence. The detection of such systems will contribute to our understanding of the dynamical histories and structural evolution of short-period substellar companions around evolved stars.

18 pages, 14 figures

References in corpus (81)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Gaia Data Release 3: Summary of the content and survey properties
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• Analytic Lightcurves for Planetary Transit Searches
• The James Webb Space Telescope
• MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones
• Local Kinematics and the Local Standard of Rest
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Las Cumbres Observatory Global Telescope Network
• Gaia Early Data Release 3: The astrometric solution
• Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the Solar neighbourhood
• batman: BAsic Transit Model cAlculatioN in Python
• Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction
• The TESS Input Catalog and Candidate Target List
• AstroImageJ: Image Processing and Photometric Extraction for Ultra-Precise Astronomical Light Curves
• AstroImageJ: Image Processing and Photometric Extraction for Ultra-Precise Astronomical Light Curves (Expanded Edition)
• Models of Giant Planet formation with migration and disc evolution
• Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments
• Evolutionary models for low-mass stars and brown dwarfs: uncertainties and limits at very young ages
• A Framework for Prioritizing the TESS Planetary Candidates Most Amenable to Atmospheric Characterization
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• Homogeneous studies of transiting extrasolar planets. IV. Thirty systems with space-based light curves
• Gravitational Instabilities in Circumstellar Disks
• Improved parameters for extrasolar transiting planets
• BANYAN. XI. The BANYAN $\Sigma$ multivariate Bayesian algorithm to identify members of young associations within 150 pc
• Improving the Efficiency of Markov Chain Monte Carlo for Analyzing the Orbits of Extrasolar Planets
• Tidal Evolution of Close-in Extra-Solar Planets
• The TESS Objects of Interest Catalog from the TESS Prime Mission
• Possible Solutions to the Radius Anomalies of Transiting Giant Planets
• The first WASP public data release
• HAT-P-16b: A 4 Mj Planet Transiting A Bright Star On An Eccentric Orbit
• Limb and gravity-darkening coefficients for the TESS satellite at several metallicities, surface gravities, and microturbulent velocities
• A new set of atmosphere and evolution models for cool T-Y brown dwarfs and giant exoplanets
• The Deuterium-Burning Mass Limit for Brown Dwarfs and Giant Planets
• The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux
• Understanding The Effects Of Stellar Multiplicity On The Derived Planet Radii From Transit Surveys: Implications for Kepler, K2, and TESS
• The "Mysterious" Origin of Brown Dwarfs
• Planetary nebulae seen with TESS: Discovery of new binary central star candidates from Cycle 1
• The Kepler Follow-Up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging
• Real-time processing of the imaging data from the network of Las Cumbres Observatory Telescopes using BANZAI
• Hot Jupiters and Cool Stars
• Observational Evidence for Tidal Destruction of Exoplanets
• PALM-3000: Exoplanet Adaptive Optics for the 5-meter Hale Telescope
• Long Term Evolution of Close Planets Including the Effects of Secular Interactions
• Evidence of an Upper Bound on the Masses of Planets and its Implications for Giant Planet Formation
• Analytic Planetary Transit Light Curves and Derivatives for Stars with Polynomial Limb Darkening
• Statistical Properties of Brown Dwarf Companions: Implications for Different Formation Mechanisms
• The Dependence of Brown Dwarf Radii on Atmospheric Metallicity and Clouds: Theory and Comparison with Observations
• On the Inference of a Star's Inclination Angle from its Rotation Velocity and Projected Rotation Velocity
• High-resolution imaging of $Kepler$ planet host candidates. A comprehensive comparison of different techniques
• Transiting exoplanets from the CoRoT space mission. XV. CoRoT-15b: a brown dwarf transiting companion
• The Rossiter-McLaughlin effect in Exoplanet Research
• pyaneti II: A multidimensional Gaussian process approach to analysing spectroscopic time-series
• Evidence for a systematic offset of $-$0.25 mas in the Gaia DR1 parallaxes
• Multicolour photometry for exoplanet candidate validation
• Speckle Observations of TESS Exoplanet Host Stars. II. Stellar Companions at 1-1000 AU and Implications for Small Planet Detection
• MuSCAT2: four-color Simultaneous Camera for the 1.52-m Telescopio Carlos Sánchez
• Impact of a new H/He equation of state on the evolution of massive brown dwarfs. New determination of the hydrogen burning limit
• K2-97b: A (Re-?)Inflated Planet Orbiting a Red Giant Star
• The Densities of Planets in Multiple Stellar Systems
• Unresolved Binary Exoplanet Host Stars Fit as Single Stars: Effects on the Stellar Parameters
• Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit
• Do close-in giant planets orbiting evolved stars prefer eccentric orbits?
• A Significant Over-Luminosity in the Transiting Brown Dwarf CWW 89Ab
• Speckle Interferometry with CMOS Detector
• Determining the true mass of radial-velocity exoplanets with Gaia: 9 planet candidates in the brown-dwarf/stellar regime and 27 confirmed planets
• Exploring the Brown Dwarf Desert: New Substellar Companions from the SDSS-III MARVELS Survey
• Predicting radial-velocity jitter induced by stellar oscillations based on Kepler data
• TOI-5005 b: A super-Neptune in the savanna near the ridge
• Constraining tidal dissipation in F-type main-sequence stars: the case of CoRoT-11
• Another Shipment of Six Short-Period Giant Planets from TESS
• Three new brown dwarfs and a massive hot Jupiter revealed by TESS around early-type stars
• $\text{TESS}$ Giants Transiting Giants I: A Non-inflated Hot Jupiter Orbiting a Massive Subgiant
• Detection of a very low mass star in an Eclipsing Binary system
• Predicting Granulation "Flicker" and Radial Velocity "Jitter" from Spectroscopic Observables
• Three low-mass companions around aged stars discovered by TESS
• Discovery of an inflated hot Jupiter around a slightly evolved star TOI-1789
• The PRL 2.5m Telescope and its First Light Instruments: FOC & PARAS-2
• Discovery and characterization of a dense sub-Saturn TOI-6651b
• The Impact of Irradiation on the Radius and Thermal Evolution of Transiting Brown Dwarfs