2002/09/04 by Michael C. Cushing, M. C. Cushing, John T. Rayner +5 · 9 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/344525
published as Astrophys.J. 582 (2003) 1066-1072 · accepted by ApJ
arxiv created 2002/09/04 · openalex publication_date 2003/01/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present medium-resolution z -, J -, and H -band spectra of four late-type dwarfs with spectral types ranging from M8 to L7.5. In an attempt to determine the origin of numerous weak absorption features throughout their near-infrared spectra, and motivated by the recent tentative identification of the E 4 Π- A 4 Π system of FeH near 1.6 μm in umbral and cool star spectra, we have compared the dwarf spectra to a laboratory FeH emission spectrum. We have identified nearly 100 FeH absorption features in the z -, J -, and H -band spectra of the dwarfs. In particular, we have identified 34 features that dominate the appearance of the H -band spectra of the dwarfs and that appear in the laboratory FeH spectrum. Finally, all of the features are either weaker or absent in the spectrum of the L7.5 dwarf, which is consistent with the weakening of the known FeH bandheads in the spectra of the latest L dwarfs.