Properties of dwarf stars in Cygnus OB2

TL;DR

This study analyzes five dwarf stars in Cygnus OB2, deriving their stellar and wind properties, ages, and chemical compositions using spectral modeling, revealing age differences within the association.

Contribution

First detailed spectral analysis of these specific Cygnus OB2 dwarf stars using TLUSTY and CMFGEN codes to determine their physical and evolutionary properties.

Findings

Lower mass stars are older than 10 Myr.

Higher mass stars are between 4-6 Myr old.

Stars show varied chemical abundances and wind properties.

Abstract

We present the results of investigation of five stars, originally classified as dwarfs, belonging to Cyg OB2 association, their stellar and wind properties. Using both TLUSTY and CMFGEN codes we derived effective temperatures, surface gravities, chemical abundances, mass-loss rates and projected rotation velocities. Due to the fact that distance to the stars is well known, we were able to estimate their luminosities. Using evolutionary models we estimated the ages of these sample stars and find that lower mass ones - MT282 and MT343 - belong to older population of the association. Their ages are greater than 10 Myr. The ages of three other stars - MT317, MT299, MT259 - are between 4-6 Myr.