Parameters of Herbig Ae/Be and Vega-type stars

TL;DR

This study determines fundamental stellar parameters for 27 young early-type stars and three suspected hot companions, using a distance-independent method based on spectral analysis, contributing to understanding star and planet formation.

Contribution

It introduces a novel distance-independent approach to estimate stellar parameters of young stars using spectral data and evolutionary models.

Findings

Most stars show IR excesses indicating disks.

The method provides accurate stellar parameters without needing distance.

Detailed analysis of individual objects like VV Ser and RR Tau.

Abstract

This work presents the determination of the effective temperature, gravity, metallicity, mass, luminosity and age of 27 young early-type stars, most of them in the age range 1-10 Myr, and three -suspected- hot companions of post-T Tauri stars belonging to the Lindroos binary sample. Most of these objects show IR excesses in their spectral energy distributions, which are indicative of the presence of disks. The work is relevant in the fields of stellar physics, physics of disks and formation of planetary systems. Spectral energy distributions and mid-resolution spectra were used to estimate the effective temperature. The comparison of the profiles of the Balmer lines with synthetic profiles provides the value of the stellar gravity. High-resolution optical observations and synthetic spectra are used to estimate the metallicity, [M/H]. Once these three parameters are known for each star, evolutionary tracks and isochrones provide estimations of the mass, luminosity, age and distance (or upper limits in some cases). The method is original in the sense that it is distance-independent, i.e. the estimation of the stellar parameters does not require, as it happens in other works, the knowledge of the distance to the object. A detailed discussion on some individual objects, in particular VV Ser, RR Tau, 49 Cet and the three suspected hot companions of post-T Tauris, is presented. The paper also shows the difficulty posed by the morphology and behaviour of the system star+disk in the computation of the stellar parameters.