Individual, Model-Independent Masses of the Closest Known Brown Dwarf Binary to the Sun

Abstract

At a distance of 2~pc, our nearest brown dwarf neighbor, Luhman 16 AB, has been extensively studied since its discovery 3 years ago, yet its most fundamental parameter -- the masses of the individual dwarfs -- has not been constrained with precision. In this work we present the full astrometric orbit and barycentric motion of Luhman 16 AB and the first precision measurements of the individual component masses. We draw upon archival observations spanning 31 years from the European Southern Observatory (ESO) Schmidt Telescope, the Deep Near-Infrared Survey of the Southern Sky (DENIS), public FORS2 data on the Very Large Telescope (VLT), and new astrometry from the Gemini South Multiconjugate Adaptive Optics System (GeMS). Finally, we include three radial velocity measurements of the two components from VLT/CRIRES, spanning one year. With this new data sampling a full period of the orbit, we use a Markov Chain Monte Carlo algorithm to fit a 16-parameter model incorporating mutual orbit and barycentric motion parameters and constrain the individual masses to be~$27.9_{-1.0}^{+1.1}$~$M_J$ for the T dwarf and~$34.2_{-1.1}^{+1.3}$~$M_J$ for the L dwarf. Our measurements of Luhman 16 AB's mass ratio and barycentric motion parameters are consistent with previous estimates in the literature utilizing recent astrometry only. The GeMS-derived measurements of the Luhman 16 AB separation in 2014-2015 agree closely with Hubble Space Telescope (HST) measurements made during the same epoch Bedin et al. 2017, and the derived mutual orbit agrees with those measurements to within the HST uncertainties of $0.3-0.4$ milliarcseconds.

Accepted for publication in the Astrophysical Journal. 2nd version: Added a reference

References in corpus (14)

• The Gaia mission
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• Transiting exoplanets from the CoRoT space mission VI. CoRoT-Exo-3b: The first secure inhabitant of the brown-dwarf desert
• Cloud structure of the nearest brown dwarfs: Spectroscopic variability of Luhman 16AB from the Hubble Space Telescope
• Multiepoch Radial Velocity Observations of L Dwarfs
• Signatures of Cloud, Temperature, and Gravity From Spectra of the Closest Brown Dwarfs
• SOPHIE velocimetry of Kepler transit candidates. VIII. KOI-205 b: a brown-dwarf companion to a K-type dwarf
• Dynamical Mass of GJ 802B: a brown dwarf in a triple system
• Precision Astrometry with Adaptive Optics
• The Mass-Luminosity Relation in the L/T Transition: Individual Dynamical Masses for the New J-Band Flux Reversal Binary SDSSJ105213.51+442255.7AB
• Characterizing the Cool KOIs. VII. Refined Physical Properties of the Transiting Brown Dwarf LHS 6343 C
• Hubble Space Telescope astrometry of the closest brown dwarf binary system -- I. Overview and improved orbit
• High-precision astrometry on the VLT/FORS1 at time scales of few days

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• Gaia Data Release 3: Stellar multiplicity, a teaser for the hidden treasure
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• COol Companions ON Ultrawide orbiTS (COCONUTS). I. A High-Gravity T4 Benchmark around an Old White Dwarf and A Re-Examination of the Surface-Gravity Dependence of the L/T Transition
• The JWST Weather Report from the Nearest Brown Dwarfs I: multi-period JWST NIRSpec + MIRI monitoring of the benchmark binary brown dwarf WISE 1049AB
• WISE2150-7520AB: A very low mass, wide co-moving brown dwarf system discovered through the citizen science project Backyard Worlds: Planet 9
• Auto-Differentiable Spectrum Model for High-Dispersion Characterization of Exoplanets and Brown Dwarfs
• Optimized modeling of Gaia-Hipparcos astrometry for the detection of the smallest cold Jupiter and confirmation of seven low mass companions
• The Oceanus Moving Group: A New 500 Myr-Old Host for the Nearest Brown Dwarf
• Global weather map reveals persistent top-of-atmosphere features on the nearest brown dwarfs
• The ESO SupJup Survey VII: Clouds and line asymmetries in CRIRES${}^{+}$ J-band spectra of the Luhman 16 binary
• Individual Dynamical Masses of DENIS J063001.4$-$184014AB Reveal A Likely Young Brown Dwarf Triple
• A Unified Spectroscopic and Photometric Model to Infer Surface Inhomogeneity: Application to Luhman 16B
• HST astrometry of the closest Brown Dwarfs -- II. Improved parameters and constraints on a third body
• One of Everything: The Breakthrough Listen Exotica Catalog
• Trigonometric parallaxes of two T dwarfs with Keck and ShaneAO astrometry