2013/06/17 by R. Carrera, E. Pancino, C. Gallart +2 · 2 citations
Chemistry · Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Calibration #Chemistry #Galaxy #Infrared #Luminosity #Metal #Metallicity #Physics #Saturation (graph theory) #Spectral line #Stars #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stt1126
12 pages, 11 figures, Accepted for publication in MNRAS
arxiv created 2013/06/17 · openalex publication_date 2013/07/01 · arxiv updated 2015/06/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We extend our previous calibration of the infrared Ca ii triplet (CaT) as a metallicity indicator to the metal-poor regime by including observations of 55 field stars with [Fe/H] down to −4.0 dex. While we previously solved the saturation at high metallicity using a combination of a Lorentzian and a Gaussian to reproduce the line profiles, in this paper we address the non-linearity at low metallicity following the suggestion of Starkenburg et al. of adding two non-linear terms to the relation among the [Fe/H], luminosity and strength of the calcium triplet lines. Our calibration thus extends from −4.0 to +0.5 in metallicity and is presented using four different luminosity indicators: V − VHB, MV, MI and MK. The calibration obtained in this paper results in a tight correlation between [Fe/H] abundances measured from high-resolution spectra and [Fe/H] values derived from the CaT, over the whole metallicity range covered.