A semi-automatic procedure for abundance determination of A- and F-type stars

TL;DR

This paper introduces a semi-automatic method for determining chemical abundances in A- and F-type stars, validated with synthetic spectra and applied to fast-rotating stars like Vega, revealing effects of rotation and inclination.

Contribution

The paper presents a novel semi-automatic procedure for abundance analysis in A- and F-type stars, including validation and application to rotating stars, accounting for observational errors and stellar inclination.

Findings

Procedure yields consistent abundances with input values.

Rotation and inclination influence abundance distribution and spectral features.

Analysis of Vega shows effects of rapid rotation and inclination on spectral lines.

Abstract

A variety of physical processes leading to different types of pulsations and chemical compositions is observed among A- and F-type stars. To investigate the underlying mechanisms responsible for these processes in stars with similar locations in the H-R diagram, an accurate abundance determination is needed, among others. Here, we describe a semi-automatic procedure developed to determine chemical abundances of various elements ranging from helium to mercury for this type of stars. We test our procedure on synthetic spectra, demonstrating that our procedure provides abundances consistent with the input values, even when the stellar parameters are offset by reasonable observational errors. For a fast-rotating star such as Vega, our analysis is consistent with those carried out with other plane-parallel model atmospheres. Simulations show that the offsets from the input abundances increase for stars with low inclination angle of about 4 degrees. For this inclination angle, we also show that the distribution of the iron abundance found in different regions is bimodal. Furthermore, the effect of rapid rotation can be seen in the peculiar behaviour of the H_beta line.