Effects of stellar rotation on young cluster HR diagrams

Abstract

This thesis investigates the effects of stellar rotation on the HR diagram location of members within young clusters. The rotational effects on luminosity and temperature of a star depend on the viewing angle and the rotation rate of the star and must be included in determining the HR diagram locations. The position of members is used as an indicator of the rotational characteristics of the individual stars. The fraction of clusters with a selected member within restricted ranges of rotation rate and viewing angle has been calculated for each selected member. These selected members are: brightest cluster member, bluest cluster member, and reddest cluster member above a luminosity cutoff. The brightest and bluest members were found to be rapidly rotating and viewed pole-on in 74% and 88% of the clusters respectively. The reddest member above a luminosity cutoff was found to be rapidly rotating and viewed equator on in 94% of the clusters.