Resolved Near-Infrared Spectroscopy of WISE J104915.57-531906.1AB: A Flux-Reversal Binary at the L dwarf/T dwarf Transition

Abstract

We report resolved near-infrared spectroscopy and photometry of the recently identified brown dwarf binary WISE J104915.57-531906.1AB, located 2.02+/-0.15 pc from the Sun. Low-resolution spectral data from Magellan/FIRE and IRTF/SpeX reveal strong H2O and CO absorption features in the spectra of both components, with the secondary also exhibiting weak CH4 absorption at 1.6 micron and 2.2 micron. Spectral indices and comparison to low-resolution spectral standards indicate component types of L7.5 and T0.5, the former consistent with the optical classification of the primary. Relative photometry reveals a flux reversal between the J- and K-bands, with the T dwarf component being brighter in the 0.95--1.3 micron range. As with other L/T transition binaries, this reversal likely reflects significant depletion of condensate opacity across the transition, a behavior that may be enhanced in WISE J1049-5319AB if the unusual red color of its L dwarf component is indicative of thick clouds. On the other hand, differing cloud properties may have modified the evolutionary paths of these two components, and we propose a scenario in which the cooler secondary could be the more massive of the two components. Fortunately, the proximity, brightness and small separation (3.12+/-0.25 AU) of this system make it amenable to astrometric and radial velocity orbit measurement during its estimated 25 yr orbit, providing a rare opportunity for the direct determination of individual brown dwarf masses and a unique benchmark for studying cloud evolution across the L dwarf/T dwarf transition.

8 pages, 5 figures SUBMITTED to ApJ (comments are welcome)

References in corpus (14)

• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• Neglected Clouds in T and Y Dwarf Atmospheres
• The 0.8-14.5 micron Spectra of Mid-L to Mid-T Dwarfs: Diagnostics of Effective Temperature, Grain Sedimentation, Gas Transport, and Surface Gravity
• Masses, Radii, and Cloud Properties of the HR 8799 Planets
• Characterizing Young Brown Dwarfs using Low Resolution Near-IR Spectra
• Hubble Space Telescope NICMOS Observations of T Dwarfs: Brown Dwarf Multiplicity and New Probes of the L/T Transition
• Discovery of a Binary Brown Dwarf at 2 Parsecs from the Sun
• Subtle Signatures of Multiplicity in Late-type Dwarf Spectra: The Unresolved M8.5 + T5 Binary 2MASS J03202839-0446358
• Discovery of Two Nearby, Peculiar L Dwarfs from the 2MASS Proper Motion Survey: Young or Metal-Rich?
• 2MASSJ035523.51+113337.4: A Young, Dusty, Nearby, Isolated Brown Dwarf Resembling A Giant Exoplanet
• First Light LBT AO Images of HR 8799 bcde at 1.65 and 3.3 Microns: New Discrepancies between Young Planets and Old Brown Dwarfs
• Discovery of a T Dwarf Binary with the Largest Known J-Band Flux Reversal
• Characterization of the Nearby L/T Binary Brown Dwarf WISE J104915.57-531906.1 at 2 Parsecs from the Sun
• Design and Construction of Absorption Cells for Precision Radial Velocities in the K Band using Methane Isotopologues

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