ULAS J141623.94+134836.3: A BLUE T DWARF COMPANION TO A BLUE L DWARF
- Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States)
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 {mu}m spectroscopy obtained with the Infrared Telescope Facility/SpeX shows strong H{sub 2}O and CH{sub 4} absorption bands, consistent with a T7.5 spectral type, and we see possible indications of NH{sub 3} absorption in the 1.0-1.3 {mu}m 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{sub eff} = 650 {+-} 60 K, log g = 5.2 {+-} 0.4 cgs, [M/H] {<=} -0.3, and K{sub zz} = 10{sup 4} cm{sup 2} s{sup -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{sup +3.0}{sub -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.
- OSTI ID:
- 21443079
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 139, Issue 6; Other Information: DOI: 10.1088/0004-6256/139/6/2448; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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