2005/02/21 by Katia Cunha, Kátia Cunha, Verne V. Smith · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/429861
published as Astrophys.J. 626 (2005) 425-430 · 18 pages, including 2 tables and 3 figures. Accepted for publication in The Astrophysical Journal
arxiv created 2005/02/21 · openalex publication_date 2005/06/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
This is a pilot study using cool dwarfs as sources with which to probe fluorine abundances via HF. This molecule is detected for the first time in young K-M dwarf members of an OB association. The targets are three low-mass stars (JW 22, JW 163, and JW 433) belonging to the Orion Nebula Cluster. The target stellar parameters were derived to be T eff = 3650, 4250, and 4400 K and log g = 3.5, 3.4, and 3.6, with corresponding stellar masses of 0.4, 0.6, and 0.7 M ☉ , for JW 22, JW 163, and JW 433, respectively. Fluorine, oxygen, and carbon abundances were derived from the HF(1-0) R 9 line along with samples of OH and CO vibrational-rotational lines present in high-resolution infrared spectra observed with the Phoenix spectrograph on the Gemini South Telescope. The fluorine and oxygen results obtained for these targets, still in the pre-main-sequence stage of evolution, agree well with the general trend defined for the Milky Way disk, the latter being deduced from observations of more evolved giant stars. In addition, the carbon and oxygen abundances obtained for the studied stars overlap results from previous studies of the more massive OB stars and FG dwarf members of the Orion Nebula Cluster. We conclude from this agreement that the fluorine abundances derived for the Orion K-M dwarfs (when there is no conspicuous evidence of disks) can be considered a good representation of the current fluorine abundance value for the Milky Way disk.