Iron abundances from optical Fe III absorption lines in B-type stellar spectra

Abstract

The role of optical Fe III absorption lines in B-type stars as iron abundance diagnostics is considered. To date, ultraviolet Fe lines have been widely used in B-type stars, although line blending can severely hinder their diagnostic power. Using optical spectra, covering a wavelength range ~ 3560 - 9200 A, a sample of Galactic B-type main-sequence and supergiant stars of spectral types B0.5 to B7 are investigated. A comparison of the observed Fe III spectra of supergiants, and those predicted from the model atmosphere codes TLUSTY (plane-parallel, non-LTE), with spectra generated using SYNSPEC (LTE), and CMFGEN (spherical, non-LTE), reveal that non-LTE effects appear small. In addition, a sample of main-sequence and supergiant objects, observed with FEROS, reveal LTE abundance estimates consistent with the Galactic environment and previous optical studies. Based on the present study, we list a number of Fe III transitions which we recommend for estimating the iron abundance from early B-type stellar spectra.

3 figures and 8 tables. Table 3 is to be published online only (included here on last page). Accepted for publication in MNRAS

References in corpus (21)

• Physical Parameters and Wind Properties of Galactic Early B Supergiants
• The VLT-FLAMES survey of massive stars: Evolution of surface N abundances and effective temperature scales in the Galaxy and Magellanic Clouds
• The VLT-FLAMES survey of massive stars: Surface chemical compositions of B-type stars in the Magellanic Clouds
• The VLT-FLAMES survey of massive stars: Wind properties and evolution of hot massive stars in the LMC
• Understanding B-type Supergiants in the Low Metallicity Environment of the SMC
• Abundance analysis of prime B-type targets for asteroseismology I. Nitrogen excess in slowly-rotating beta Cephei stars
• Predicted FeII Emission-Line Strengths from Active Galactic Nuclei
• Optical Recombination Lines of Heavy-elements in Giant Extragalactic HII Regions
• Quantitative studies of the Far-UV, UV and optical spectra of late O and early B-type supergiants in the Magellanic Clouds
• B-type Supergiants in the SMC: Chemical compositions and comparison of static and unified models
• Element Ratios and the Formation of the Stellar Halo
• Chemical composition of B-type supergiants in the OB8, OB10, OB48, OB78 associations of M31
• Metallicities of the beta Cephei stars from low-resolution ultraviolet spectra
• Iron abundance in HII regions
• Theoretical FeI/II/III Emission-Line Strengths from Active Galactic Nuclei with Broad-Line Regions
• A non-LTE analysis of the spectra of two narrow lined main sequence stars in the SMC
• Iron abundances of B-type post-Asymptotic Giant Branch stars in globular clusters: Barnard 29 in M 13 and ROA 5701 in omega Cen
• ORFEUS-II Observations of the Ultraviolet-Bright Star Barnard 29 in M13
• M31N 2005-09c: a fast FeII nova in the disk of M31
• A non-LTE abundance analysis of the post-AGB star ROA 5701
• The properties of optical FeII emission lines of AGN with double-peaked broad emission lines

Cited by in corpus (6)

• The atmospheric parameters and spectral interpolator for the stars of MILES
• Red Supergiants as Cosmic Abundance Probes: The Magellanic Clouds
• The ${}^7$Be II Resonance Lines in Two Classical Novae V5668 Sgr and V2944 Oph
• The Gaia-ESO Survey: The analysis of the hot-star spectra
• Gas-phase Fe/O and Fe/N abundances in Star-Forming Regions. Relations between nucleosynthesis, metallicity and dust
• The C60:C60+ ratio in diffuse and translucent interstellar clouds