Letter to the Editor

The astrophysical parameters of chemically peculiar stars from automatic methods

Department of Theoretical Physics and Astrophysics, Masaryk University, Kotlářská 2, 611 37, Brno, Czech Republic
e-mail: epaunzen@physics.muni.cz

Received: 27 September 2023
Accepted: 26 February 2024

Abstract

Context. The chemically peculiar (CP) stars of the upper main sequence are excellent astrophysical laboratories for investigating the diffusion, mass loss, rotational mixing, and pulsation in the presence and absence of a stable local magnetic field. For this, we need a homogeneous set of parameters, such as effective temperature (T_eff) and surface gravity (log g), to locate the stars in the Hertzsprung-Russell diagram so that we can then estimate the mass, radius, and age.

Aims. In recent years, the results of several automatic pipelines have been published; these use various techniques and data sets, including T_eff and log g values for millions of stars. Because CP stars are known to have flux anomalies, these astrophysical parameters must be tested for their reliability and usefulness. If the outcome is positive, these can be used to analyse the new and faint CP stars published recently.

Methods. I compared published T_eff and log g values of a set of CP stars, which are mostly based on high-resolution spectroscopy, with values from four automatic pipeline approaches. In doing so, I searched for possible correlations and offsets.

Results. I present a detailed statistical analysis of a comparison between the ‘standard’ and published T_eff and log g values. The accuracy depends on the presence of a magnetic field and the spectral type of the CP subgroups. However, I obtain standard deviations of between 2% and 20%.

Conclusions. Considering the statistical errors, the astrophysical parameters from the literature can be used for CP stars, although caution is advised for magnetic CP stars.