EPIC 219388192 b - an inhabitant of the brown dwarf desert in the Ruprecht 147 open cluster

Abstract

We report the discovery of EPIC 219388192 b, a transiting brown dwarf in a 5.3-day orbit around a member star of Ruprecht-147, the oldest nearby open cluster association, which was photometrically monitored by K2 during its Campaign 7. We combine the K2 time-series data with ground-based adaptive optics imaging and high resolution spectroscopy to rule out false positive scenarios and determine the main parameters of the system. EPIC 219388192 b has a radius of $R_{\mathrm{b}}$=$0.937\pm 0.042$~${\mathrm{R}}_{\mathrm{Jup}}$ and mass of $M_{\mathrm{b}}$=$36.50\pm 0.09$~${\mathrm{M}}_{\mathrm{Jup}}$, yielding a mean density of $59.0\pm 8.1$~$\mathrm{g}\mathrm{c}{\mathrm{m}}^{-3}$. The host star is nearly a Solar twin with mass $M_{\star }$=$0.99\pm 0.05$~${\mathrm{M}}_{\odot }$, radius $R_{\star }$=$1.01\pm 0.04$~${\mathrm{R}}_{\odot }$, effective temperature ${\mathrm{T}}_{\mathrm{eff}}$=$5850\pm 85$~K and iron abundance [Fe/H]=$0.03\pm 0.08$~dex. Its age, spectroscopic distance, and reddening are consistent with those of Ruprecht-147, corroborating its cluster membership. EPIC 219388192 b is the first brown dwarf with precise determinations of mass, radius and age, and serves as benchmark for evolutionary models in the sub-stellar regime.

13 pages, 11 figures, 4 tables, submitted to AAS Journals

References in corpus (16)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Dartmouth Stellar Evolution Database
• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• Tidal dissipation in stars and giant planets
• Prospects for the Characterization and Confirmation of Transiting Exoplanets via the Rossiter-McLaughlin Effect
• Determining stellar macroturbulence using asteroseismic rotational velocities from Kepler
• Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence
• WIYN Open Cluster Study. LX. Spectroscopic Binary Orbits in NGC 6819
• Evolution of angular-momentum-losing exoplanetary systems : Revisiting Darwin stability
• SOPHIE velocimetry of Kepler transit candidates. VIII. KOI-205 b: a brown-dwarf companion to a K-type dwarf
• Time variation of Kepler transits induced by stellar rotating spots - a way to distinguish between prograde and retrograde motion I. Theory
• Kepler423b: a half-Jupiter mass planet transiting a very old solar-like star
• The stellar obliquity, planet mass, and very low albedo of Qatar-2 from K2 Photometry
• Interplay of tidal evolution and stellar wind braking in the rotation of stars hosting massive close-in planets
• K2-98 b: A 32-M${}_{\oplus }$ Neptune-sized planet in a 10-day orbit transiting an F8 star

Cited by in corpus (24)

• When Do Stalled Stars Resume Spinning Down? Advancing Gyrochronology with Ruprecht 147
• Age Determination in Upper Scorpius with Eclipsing Binaries
• New low-mass eclipsing binary systems in Praesepe discovered by K2
• A high binary fraction for the most massive close-in giant planets and brown dwarf desert members
• The transiting multi-planet system HD3167: a 5.7 MEarth Super-Earth and a 8.3 MEarth mini-Neptune
• Two intermediate-mass transiting brown dwarfs from the TESS mission
• Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit
• TOI-811b and TOI-852b: New transiting brown dwarfs with similar masses and very different radii and ages from the TESS mission
• WD1032+011, an inflated brown dwarf in an old eclipsing binary with a white dwarf
• TOI-503: The first known brown dwarf-Am star binary from the TESS mission
• Ruprecht 147 DANCe I. Members, empirical isochrone, luminosity and mass distributions
• Three new brown dwarfs and a massive hot Jupiter revealed by TESS around early-type stars
• NGTS-19b : A high mass transiting brown dwarf in a 17-day eccentric orbit
• Improved radius determinations for the transiting brown dwarf population in the era of Gaia and TESS
• Rotation periods for cool stars in the open cluster Ruprecht 147 (NGC 6774): Implications for gyrochronology
• TOI 694 b and TIC 220568520 b: Two Low-Mass Companions Near the Hydrogen Burning Mass Limit Orbiting Sun-like Stars
• No "Maunder minimum" candidates in M67: mitigating interstellar contamination of chromospheric emission lines
• Three low-mass companions around aged stars discovered by TESS
• The multi-planet system TOI-421 -- A warm Neptune and a super puffy mini-Neptune transiting a G9 V star in a visual binary
• The Sonora Brown Dwarf Atmosphere and Evolution Models I. Model Description and Application to Cloudless Atmospheres in Rainout Chemical Equilibrium
• TYCHO -- Realistically Simulating Exoplanets within Stellar Clusters I: Improving the Monte Carlo Approach
• Scaling K2. V. Statistical Validation of 60 New Exoplanets From K2 Campaigns 2-18
• Evidence of Radius Inflation Based on 50 Transiting Brown Dwarfs and Low-mass Stellar Companions
• Secondary eclipses of two brown dwarfs in the K2 fields: detection by multiple dataset merging