Halo Stars near the Hydrogen?burning Limit: The M/L Subdwarf Transition1

2006/01/01 by J. E. Gizis, John E. Gizis, James Harvin +1 · 25 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Galactic halo #Halo #Horizontal branch #Spectral line #Stars #Stellar, planetary, and galactic studies #Subdwarf #astro-ph

paper · pdf · doi:10.1086/508514

published in The Astronomical Journal 132(6), 2372-2375 (Institute of Physics) · accepted to Astronomical Journal

openalex publication_date 2006/01/01 · arxiv created 2006/08/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06

Abstract

We present the first far-red spectra of the L subdwarf 2MASS J16262034+3925190 and the late-M/early-L subdwarf 2MASS J16403197+1231068. We confirm the ultracool subdwarf nature of these objects. Like an L4 dwarf, 2M 1626+3925 shows strong K I absorption and is very similar to, but hotter than, the late-L subdwarf 2MASS J05325346+8246465. It is unambiguously an L subdwarf. 2M 1640+1231 is very similar to SSSPM J1444-2019, which has been classified as sdM9 or early sdL. In contrast to the hotter M subdwarfs, L subdwarfs are characterized by not only enhanced hydrides but also strong TiO. Progress in a classification system requires identification of more subdwarfs to map out their variations.

Citations

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