2004/09/08 by Adam J. Burgasser · 102 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Brown dwarf #Galactic halo #Galaxy #Halo #Metallicity #Physics #Population #Sky #Stars #Stellar, planetary, and galactic studies #Subdwarf #White dwarf #astro-ph
paper · pdf · doi:10.1086/425418
published in The Astrophysical Journal 614(1), L73-L76 (IOP Publishing) · 11 pages, 3 figures, accepted for publication ApJ Letters, v. 614 October 2004
arxiv created 2004/09/08 · openalex publication_date 2004/09/08 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
I report the discovery of the second L subdwarf identified in the Two Micron All Sky Survey, 2MASS J16262034+3925190. This high proper motion object (μ = 1 27 ± 0 03 yr -1 ) exhibits near-infrared spectral features indicative of a subsolar metallicity L dwarf, including strong metal hydride and H 2 O absorption bands, pressure-broadened alkali lines, and blue near-infrared colors caused by enhanced collision-induced H 2 absorption. This object is of later type than any of the known M subdwarfs but does not appear to be as cool as the apparently late-type sdL 2MASS 0532+8246. The radial velocity ( V rad = -260 ± 35 km s -1 ) and estimated tangential velocity ( V tan ≈ 90-210 km s -1 ) of 2MASS 1626+3925 indicate membership in the Galactic halo, and this source is likely near or below the hydrogen-burning minimum mass for a metal-poor star. L subdwarfs such as 2MASS 1626+3925 are useful probes of gas and condensate chemistry in low-temperature stellar and brown dwarf atmospheres, but more examples are needed to study these objects as a population as well as to define a rigorous classification scheme.