The young open cluster Trumpler 3

TL;DR

This study provides detailed photometric and spectroscopic analysis of the young open cluster Trumpler 3, determining its fundamental parameters, mass, and dynamical state, and discovering variable stars within its vicinity.

Contribution

It offers the first comprehensive set of parameters for Trumpler 3, including age, distance, mass, and variable star content, improving understanding of this poorly studied cluster.

Findings

Age of 70±10 Myr established

Total mass of 270±40 solar masses determined

24 variable stars discovered, one likely cluster member

Abstract

We present a photometric and spectroscopic study of the poorly investigated open cluster Trumpler~3. Basic parameters such as the age of $70\pm10$ Myr, the color excess $E(B-V)=0.30\pm0.02$ mag, the distance of $0.69\pm0.03$ kpc and the limiting radius of 12' were redetermined and compared with previous preliminary studies. The distance of $0.65\pm0.09$ kpc was determined independently by spectral parallaxes. Simultaneously, our analysis allowed us to estimate a total number of members to be $N_{\rm{tot}}=570\pm90$ and a total mass of the cluster to be $M_{\rm{tot}}=270\pm40$ $\rm{M}_{\odot}$. We also determined a state of cluster's dynamical evolution. We conclude that Trumpler~3 is a young low-massive stellar ensemble with a typical mass function slope, located near to the outer edge of the Galaxy's Orion Spur. As a result of a wide-field search for short period variable stars, 24 variables were discovered in the cluster's area. Only one of them -- a variable of the $\gamma$-Dor type -- was found to be a likely cluster member.