A T8.5 Brown Dwarf Member of the Xi Ursae Majoris System

Abstract

The Wide-field Infrared Survey Explorer has revealed a T8.5 brown dwarf (WISE J111838.70+312537.9) that exhibits common proper motion with a solar-neighborhood (8 pc) quadruple star system - Xi Ursae Majoris. The angular separation is 8.5 arc-min, and the projected physical separation is about 4000 AU. The sub-solar metallicity and low chromospheric activity of Xi UMa A argue that the system has an age of at least 2 Gyr. The infrared luminosity and color of the brown dwarf suggests the mass of this companion ranges between 14 and 38 Jupiter masses for system ages of 2 and 8 Gyr respectively.

arXiv commentAJ in press, 12 pages LaTeX with 6 figures. More astrometric data and a laser guide star adaptive optics image added

References in corpus (28)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• A Method of Correcting Near-Infrared Spectra for Telluric Absorption
• The Infrared Telescope Facility (IRTF) Spectral Library: Cool Stars
• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• Absolute Calibration of the Infrared Array Camera on the Spitzer Space Telescope
• A Unified Near Infrared Spectral Classification Scheme for T Dwarfs
• Neglected Clouds in T and Y Dwarf Atmospheres
• The Spectra of T Dwarfs I: Near-Infrared Data and Spectral Classification
• The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)
• The Discovery of Y Dwarfs Using Data from the Wide-field Infrared Survey Explorer (WISE)
• Further Defining Spectral Type "Y" and Exploring the Low-mass End of the Field Brown Dwarf Mass Function
• Beyond the T Dwarfs: Theoretical Spectra, Colors, and Detectability of the Coolest Brown Dwarfs
• The Carnegie Supernova Project: The Low-Redshift Survey
• Low-Mass Tertiary Companions to Spectroscopic Binaries I: Common Proper Motion Survey for Wide Companions using 2MASS
• A Systematic Study of Departures from Chemical Equilibrium in the Atmospheres of Substellar Mass Objects
• High Precision Dynamical Masses of Very Low Mass Binaries
• JHK Magnitudes for L and T Dwarfs and Infrared Photometric Systems
• The discovery of a very cool, very nearby brown dwarf in the Galactic plane
• Revised Coordinates and Proper Motions of the Stars in the Luyten Half-Second Catalogue
• Discovery of the benchmark metal poor T8 dwarf BD+01 2920B
• WISE J163940.83-684738.6: A Y Dwarf identified by Methane Imaging
• Parallaxes and Proper Motions of Ultracool Brown Dwarfs of Spectral Types Y and Late T
• Kinematics of the chromospherically active binaries and evidence of an orbital period decrease in binary evolution
• Preliminary Design of The Wide-Field Infrared Survey Explorer (WISE)
• The night-sky at the Calar Alto Observatory II: The sky at the near infrared
• Dynamical masses for the nearest brown dwarf binary: Epsilon Indi Ba, Bb

Cited by in corpus (18)

• Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects
• The Field Substellar Mass Function Based on the Full-sky 20-pc Census of 525 L, T, and Y Dwarfs
• The 10 parsec sample in the Gaia era
• Preliminary Trigonometric Parallaxes of 184 Late-T and Y Dwarfs and an Analysis of the Field Substellar Mass Function into the "Planetary" Mass Regime
• Photometry and Proper Motions of M, L, and T Dwarfs from the Pan-STARRS1 3$\pi$ Survey
• Wide, Cool and Ultracool Companions to Nearby Stars from Pan-STARRS1
• The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data
• The Exemplar T8 Subdwarf Companion of Wolf 1130
• Rotation Periods, Inclinations, and Obliquities of Cool Stars Hosting Directly Imaged Substellar Companions: Spin-Orbit Misalignments are Common
• Self-consistent Models of Y Dwarf Atmospheres with Water Clouds and Disequilibrium Chemistry
• A circular polarisation survey for radio stars with the Australian SKA Pathfinder
• The Hawaii Infrared Parallax Program. V. New T-Dwarf Members and Candidate Members of Nearby Young Moving Groups
• Discovery of a Low-Luminosity, Tight Substellar Binary at the T/Y Transition
• The Second Arecibo Search for 5 GHz Radio Flares from Ultracool Dwarfs
• Wolf 1130: A Nearby Triple System Containing a Cool, Ultramassive White Dwarf
• Resolved Spectroscopy of the T8.5 and Y0-0.5 Binary WISEPC J121756.91+162640.2AB
• USco1621 B and USco1556 B: Two wide companions at the deuterium-burning mass limit in Upper Scorpius
• Using Old and New Approaches: Determining Physical Properties of Brown Dwarfs with Empirical Relations and Machine Learning Models