H and K Band Methane Features in an L Dwarf, 2MASS 0920+35

Abstract

We have obtained near-infrared spectra of three L dwarfs discovered by 2MASS, 1506+13 (L3), 1507-16 (L5), and 0920+35 (L6.5). From the comparison of the H and K band spectra of these L dwarfs, we have found the presence of methane absorption in 0920+35. This implies that detectable methane absorption in the H and K bands, usually considered the signature of a T dwarf, can be present in objects classified optically as late L. Methane detection in L dwarfs is consistent with the presence of a dust layer deep in the atmosphere as the unified model of Tsuji suggests.

Accepted for publication in ApJ Letters; 8 pages, 4 figures

References in corpus (1)

• Near-Infrared Spectral Classification of late-M and L Dwarfs

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