文章基本信息

标题：A Statistical Survey of Peculiar L and T Dwarfs in SDSS, 2MASS, and WISE
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作者：Kendra Kellogg ; Stanimir Metchev ; Paulo A. Miles-Páez 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2017
卷号：154
期号：3
DOI：10.3847/1538-3881/aa83b0
语种：English
出版社：American Institute of Physics
摘要：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 ( 2.1%) and another 8 (1.9%) are unusually red, with no signatures of youth. With a spectroscopic 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 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.
关键词：binaries: close;brown dwarfs;infrared: stars;stars: individual (2MASS J03530419+0418193);stars: late-type;stars: peculiar Supporting material: extended figure; machine-readable tables