Abundances of disk and bulge giants from hi-res optical spectra: I. O, Mg, Ca, and Ti in the Solar neighborhood and Kepler field samples
arXiv:1611.05462 · doi:10.1051/0004-6361/201629128
Abstract
The galactic bulge is a significant part of our galaxy, but it is hard to observe, being both distant and covered by dust in the disk. Therefore there do not exist many hi-res optical spectra of bulge stars with large wavelength coverage, whose determined abundances can be compared with nearby, similarly analyzed stellar samples. We aim to determine the, for chemical evolution models, so important alpha elements of a sample of bulge giants using hi-res optical spectra with large wavelength coverage. The abundances found will be compared to similarly derived abundances from similar spectra of similar stars in the local thin and thick disks. In this first paper we focus on the Solar neighborhood reference sample. We use spectral synthesis to derive the stellar parameters as well as the elemental abundances of both the local as well as the bulge samples of giants. Special care is taken to benchmark our method of determining stellar parameters against independent measurements of effective temperatures from angular diameter measurements and surface gravities from asteroseismology. In this first paper we present the method used to determine the stellar parameters as well as the elemental abundances, evaluate them, and present the results for our local disk sample of 291 giants. When comparing our determined spectroscopic temperatures to those derived from angular diameter measurements, we reproduce these with a systematic difference of +10 K and a standard deviation of 53 K. The spectroscopic gravities are reproducing the ones determined from asteroseismology with a systematic offset of +0.10 dex and a standard deviation of 0.12 dex. When it comes to the abundance trends, our sample of local disk giants is closely following that of other works analyzing solar neighborhood dwarfs, showing that the much brighter giant stars are as good abundance probes as the often used dwarfs.
arXiv commentAccepted for publication in A&A
References in corpus (20)
- The chemical composition of the Sun
- PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
- NLTE line formation of Fe in late-type stars II: 1D spectroscopic stellar parameters
- Gaia FGK Benchmark Stars - Metallicity
- Gaia FGK Benchmark Stars: Effective temperatures and surface gravities
- TEXES: A Sensitive High-Resolution Grating Spectrograph for the Mid-Infrared
- Oxygen, Sodium, Magnesium and Aluminium as tracers of the Galactic Bulge Formation
- Chemical similarities between Galactic bulge and local thick disk red giants: O, Na, Mg, Al, Si, Ca and Ti
- Alpha element abundances and gradients in the Milky Way bulge from FLAMES-GIRAFFE spectra of 650 K giants
- Both accurate and precise gf-values for FeII lines
- Oxygen abundances in the Galactic Bulge: evidence for fast chemical enrichment
- Gaia FGK benchmark stars: abundances of alpha and iron-peak elements
- Experimental f-value and isotopic structure for the Ni I line blended with [OI] at 6300A
- Non-LTE oxygen line formation in 3D hydrodynamic model stellar atmospheres
- Fe I Oscillator Strengths for the Gaia-ESO Survey
- Chemical abundances for 11 bulge stars from high-resolution, near-IR spectra
- Constraints on the Formation of the Galactic Bulge from Na, Al, and Heavy Element Abundances in Plaut's Field
- Fe I Oscillator Strengths for Transitions from High-lying Even-Parity Levels
- Experimental and theoretical oscillator strengths of Mg I for accurate abundance analysis
- The Milky Way Bulge: Observed properties and a comparison to external galaxies
Cited by in corpus (8)
- Abundances of disk and bulge giants from high-resolution optical spectra -- IV. Zr, La, Ce, Eu
- Abundances of disk and bulge giants from hi-res optical spectra: II. O, Mg, Ca, and Ti in the bulge sample
- Evidence against anomalous compositions for giants in the Galactic Nuclear Star Cluster
- Modelling the chemical evolution of Zr, La, Ce and Eu in the Galactic discs and bulge
- Exploring the Chemical Composition and Double Horizontal Branch of the Bulge Globular Cluster NGC 6569
- Determination of robust metallicities for metal-rich red giant branch stars
- Abundances in Galactic Bulge planetary nebulae from optical, ultraviolet and infrared observations
- Rubidium abundances in solar metallicity stars