First Stars XIV. Sulfur abundances in extremely metal-poor (EMP) stars

Abstract

Sulfur is important: the site of its formation is uncertain, and at very low metallicity the trend of [S/Fe] against [Fe/H] is controversial. Below [Fe/H]=-2.0, [S/Fe] remains constant or it decreases with [Fe/H], depending on the author and the multiplet used in the analysis. Moreover, although sulfur is not significantly bound in dust grains in the ISM, it seems to behave differently in DLAs and in old metal-poor stars. We aim to determine precise S abundance in a sample of extremely metal-poor stars taking into account NLTE and 3D effects. NLTE profiles of the lines of the multiplet 1 of SI have been computed using a new model atom for S. We find sulfur in EMP stars to behave like the other alpha-elements, with [S/Fe] remaining approximately constant for [Fe/H]<-3. However, [S/Mg] seems to decrease slightly as a function of [Mg/H]. The overall abundance patterns of O, Na, Mg, Al, S, and K are best matched by the SN model yields by Heger & Woosley. The [S/Zn] ratio in EMP stars is solar, as found also in DLAs. We obtain an upper limit on the abundance of sulfur, [S/Fe] < +0.5, for the ultra metal-poor star CS 22949-037. This, along with a previous reported measurement of zinc, argues against the conjecture that the light-element abundances pattern in this star, and, by analogy, the hyper metal-poor stars HE 0107-5240 and HE 1327-2326, are due to dust depletion.

10 pages, accepted for publication in A&A

References in corpus (15)

• Galactic chemical evolution: Carbon through Zinc
• Nucleosynthetic signatures of the first stars
• Velocity-Metallicity Correlation for high-z DLA Galaxies: Evidence for a Mass-Metallicity Relation?
• First stars VII. Lithium in extremely metal poor dwarfs
• HE 1327-2326, an unevolved star with [Fe/H]<-5.0. II. New 3D-1D corrected abundances from a VLT/UVES spectrum
• Sulphur and zinc abundances in Galactic halo stars revisited
• NLTE determination of the sodium abundance in a homogeneous sample of extremely metal-poor stars
• NLTE determination of the aluminium abundance in a homogeneous sample of extremely metal-poor stars
• Evolution of the Barium abundance in the early Galaxy from a NLTE analysis of the Ba lines in a homogeneous sample of EMP stars
• The forbidden 1082 nm line of sulphur: the photospheric abundance of sulphur in the Sun and 3D effects
• Excitation mechanisms in newly discovered H2-bearing Damped Lyman-alpha clouds: systems with low molecular fractions
• A new comprehensive set of elemental abundances in DLAs III. Star formation histories
• Sulphur abundances from the SI near-infrared triplet at 1045 nm
• Could the Ultra Metal-poor Stars be Chemically Peculiar and Not Related to the First Stars?
• Sulphur abundances in disk stars as determined from the forbidden 10821 A [SI] line

Cited by in corpus (42)

• Near-Field Cosmology with Metal-Poor Stars
• The Most Metal-Poor Stars. IV. The Two Populations With [Fe/H] < -3.0
• Using chemical tagging to redefine the interface of the Galactic disk and halo
• Binarity in Carbon-Enhanced Metal-Poor stars
• Pre-galactic metal enrichment - The chemical signatures of the first stars
• Systematic non-LTE study of the $-2.6\le$ [Fe/H] $\le 0.2$ F and G dwarfs in the solar neighbourhood. II. Abundance patterns from Li to Eu
• Abundance Profiling of Extremely Metal-Poor Stars and Supernova Properties in the Early Universe
• JINAbase: A database for chemical abundances of metal-poor stars
• The first carbon-enhanced metal-poor star found in the Sculptor dwarf spheroidal
• High-resolution abundance analysis of very metal-poor r-I stars
• Probing the existence of very massive first stars
• The Gaia-ESO Survey: Galactic evolution of sulphur and zinc
• The Galactic evolution of phosphorus
• NLTE determination of the calcium abundance and 3D corrections in extremely metal-poor stars
• Detection of Neutral Phosphorus in the Near Ultraviolet Spectra of Late-Type Stars
• Chemical abundances of damped Lyman alpha systems in the XQ-100 survey
• The chemistry of the most metal-rich damped Lyman $\alpha$ systems at z$\sim 2$ II. Context with the Local Group
• GIANO Y-band spectroscopy of dwarf stars: Phosphorus, Sulphur, and Strontium abundances
• The Chemical Compositions of Very Metal-Poor Stars HD 122563 and HD 140283; A View From the Infrared
• The Chemical Evolution of Phosphorus
• The AMBRE Project: Origin and evolution of sulfur in the Milky Way
• Sulphur in the Sculptor dwarf spheroidal galaxy - Including NLTE corrections
• Searching for Dust around Hyper Metal-Poor Stars
• The chemical connection between damped Lyman-α systems and Local Group dwarf galaxies
• Sulphur abundances in halo giants from the [S I] line at 1082 nm and the S I triplet around 1045 nm
• The Galactic evolution of sulphur as traced by globular clusters
• An upper limit on the sulphur abundance in HE 1327-2326
• Abundances of the light elements from UV (HST) and red (ESO) spectra in the very old star HD 84937
• Titans metal-poor reference stars II. Red giants and CEMP stars
• Clues on the Galactic evolution of sulphur from star clusters
• Chemical Compositions of Red Giant Stars from Habitable Zone Planet Finder Spectroscopy
• A Search for Boron in Damped Lyα Systems
• Behavior of [S/Fe] in Very Metal-Poor Stars from the S I 1.046 micron Lines Revisited
• Sulphur in the metal poor globular cluster NGC 6397
• Sulfur abundances in three Galactic clusters: Ruprecht 106, Trumpler 5 and Trumpler 20
• Influence of departures from LTE on determinations of the sulfur abundances in A-K type stars
• Be, V and Cu in the halo star CS 31082-001 from near-UV spectroscopy
• CEMPlifying reionization
• Physical Conditions and Chemical Abundances of the Variable Planetary Nebula IC 4997
• Sulfur abundances in the Galactic bulge and disk
• Gaia FGK Benchmark Stars: Selecting Infrared Lines for Abundance Determination
• On the Galactic chemical evolution of sulphur. Sulphur abundances from the [S i] 1082 nm line in giants