ULAS J141623.94+134836.3: A BLUE T DWARF COMPANION TO A BLUE L DWARF
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Burgasser_ULAS Ji4i623.94.pdf
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Author(s)
Burgasser, Adam J.
Looper, Dagny L.
Rayner, John T.
Date Issued
April 2010
Journal
The Astronomical Journal
Publisher
IOP Publishing
Citation
Burgasser, Adam J., Dagny Looper, and John T. Rayner. “ULAS J141623.94+134836.3: A BLUE T DWARF COMPANION TO A BLUE L DWARF.” The Astronomical Journal 139, no. 6 (June 1, 2010): 2448–2454.
Version
Original manuscript
Abstract
We confirm the substellar nature of ULAS J141623.94+134836.3 (aka SDSS J1416+1348B), a common proper motion companion to the blue L dwarf SDSS J141624.08+134826.7 identified by Burningham et al. and Scholz. Low-resolution 0.8-2.4 μm spectroscopy obtained with the Infrared Telescope Facility/SpeX shows strong H[subscript 2]O and CH[subscript 4] absorption bands, consistent with a T7.5 spectral type, and we see possible indications of NH[subscript 3] absorption in the 1.0-1.3 μm region. More importantly, the spectrum of SDSS J1416+1348B shows a broadened Y-band peak and highly suppressed K-band flux, both indicative of high surface gravity and/or subsolar metallicity. These traits are verified through spectral model fits, from which we derive atmospheric parameters T [subscript eff] = 650 ± 60 K, log g = 5.2 ± 0.4 cgs, [M/H] ≤ –0.3, and K[subscript zz] = 10[superscript 4] cm[superscript 2] s[superscript –1], the temperature being significantly warmer than that estimated by Burningham et al. These fits also indicate a model-dependent spectroscopic distance of 10.6[+3.0 over –2.8] pc for SDSS J1416+1348B, formally consistent with the 7.9 ± 1.7 pc astrometric distance for SDSS J1416+1348A from Scholz. The common peculiarities of these two co-spatial, co-moving sources suggest that their unusual blue colors—and those of other blue L and T dwarfs in general—arise from age/gravity or metallicity effects, rather than cloud properties alone.
MIT Department
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1088/0004-6256/139/6/2448
