A critical evaluation of the elemental abundances and evolutionary status of 15 Vul (HD 189849): The first identification of an evolved Am star

Abstract

Understanding the evolution of metallic-line (Am) stars requires well determined atmospheric parameters and abundance patterns of the selected candidates. In this study, we presented a detailed abundance analysis of 15 Vul (HD 189849), identified as a marginal Am star, using a combination of equivalent width and spectrum synthesis techniques, under the LTE assumption. We compared our findings to previous analyses of the star, providing critique on both their results and our own. Our results suggest that although 15 Vul exhibits some underabundances of calcium and scandium, which are typically associated with Am stars, it might be more accurately identified as a normal A star in terms of its abundance pattern of all other elements and microturbulence velocity. The star's position on the HR diagram, along with our findings, may indicate that it is potentially a classical Am star that has evolved into the subgiant phase as a "quasi-normal" star. This may be the first identification of an evolved Am star.

arXiv commentTable 1 is available online

References in corpus (23)

• Gaia Data Release 3: Summary of the content and survey properties
• The SIMBAD astronomical database
• The VizieR database of Astronomical Catalogues
• The Galactic Thick Disk Stellar Abundances
• The Updated BaSTI Stellar Evolution Models and Isochrones: I. Solar Scaled Calculations
• Improved Laboratory Transition Probabilities for Neutral Chromium and Re-determination of the Chromium Abundance for the Sun and Three Stars
• Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-process Rich, Metal-Poor Stars, and Rare Earth Lab Data
• Improved Ti II log(gf) Values and Abundance Determinations in the Photospheres of the Metal-Poor Star HD 84937
• Improved Ni I log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
• Correcting the spectroscopic surface gravity using transits and asteroseismology. No significant effect on temperatures or metallicities with ARES+MOOG in LTE
• Atmospheric velocity fields in tepid main sequence stars
• Gaia FGK Benchmark stars: Opening the black box of stellar element abundance determination
• Hyperfine Splitting in the VALD Database of Spectral-line Parameters
• Improved V II log($gf$) Values, Hyperfine Structure Constants, and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
• DECH: Software Package for Astronomical Spectral Data Processing and Analysis
• Abundances in HD27411 and the helium problem in Am stars
• Lithium, Sodium, and Potassium Abundances in Sharp-Lined A-Type Stars
• Scandium: A key element for understanding Am stars
• Photospheric carbon, nitrogen, and oxygen abundances of A-type main-sequence stars
• HERMES spectroscopy of normal A and Am stars
• IRFM Temperature Calibrations for the Vilnius, Geneva, RI(C) and DDO Photometric Systems
• Non-LTE analysis of the Si II lines in iota Her with various atomic data sets
• Lithium in field Am and normal A-F-type stars