Astron. J., 154, 112-112 (2017/September-0)
A statistical survey of peculiar L and T dwarfs in SDSS, 2MASS, and WISE.
KELLOGG K., METCHEV S., MILES-PAEZ P.A. and TANNOCK M.E.
Abstract (from CDS):
We present the final results from a targeted search for brown dwarfs with unusual near-infrared colors. From a positional cross-match of the Sloan Digital Sky Survey (SDSS), 2-Micron All-Sky Survey (2MASS), and Wide-Field Infrared Survey Explorer (WISE) catalogs, we have identified 144 candidate peculiar L and T dwarfs. Spectroscopy confirms that 20 of the objects are peculiar or are candidate binaries. Of the 420 objects in our full sample 9 are young ( 200 Myr; 2.1%) and another 8 (1.9%) are unusually red, with no signatures of youth. With a spectroscopic J-Ks color of 2.58 ± 0.11 mag, one of the new objects, the L6 dwarf 2MASS J03530419+0418193, is among the reddest field dwarfs currently known and is one of the reddest objects with no signatures of youth known to date. We have also discovered another potentially very-low-gravity object, the L1 dwarf 2MASS J00133470+1109403, and independently identified the young L7 dwarf 2MASS J00440332+0228112, which was first reported by Schneider and collaborators. Our results confirm that signatures of low gravity are no longer discernible in low to moderate resolution spectra of objects older than ∼200 Myr. The 1.9% of unusually red L dwarfs that do not show other signatures of youth could be slightly older, up to ∼400 Myr. In this case a red J-Ks color may be more diagnostic of moderate youth than individual spectral features. However, its is also possible that these objects are relatively metal-rich, and thus have enhanced atmospheric dust content.
© 2017. The American Astronomical Society. All rights reserved.
binaries: close - brown dwarfs - infrared: stars - stars: individual: 2MASS J03530419+0418193 - stars: late-type - stars: peculiar - stars: peculiar
VizieR on-line data:
<Available at CDS (J/AJ/154/112): table1.dat table2.dat table3.dat table4.dat>
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