Characterization of the Red Giant HR 2582 Using the CHARA Array

TL;DR

This study uses interferometry to measure fundamental parameters of the red giant HR 2582, providing data to evaluate stellar evolution models despite current measurement uncertainties.

Contribution

First direct measurement of HR 2582's angular diameter and physical parameters, combined with stellar models to estimate its evolutionary state.

Findings

Measured angular diameter: 1.006+/-0.020 mas

Estimated stellar radius: 35.76+/-5.31 R_Sun

Star's age: approximately 165 Myr

Abstract

We present the fundamental parameters of HR 2582, a high-mass red giant star whose evolutionary state is a mystery. We used the CHARA Array interferometer to directly measure the star's limb-darkened angular diameter (1.006+/-0.020 mas) and combined our measurement with parallax and photometry from the literature to calculate its physical radius (35.76+/-5.31 R_Sun), luminosity (517.8+/-17.5 L_Sun), bolometric flux (14.8+/-0.5 e-8 erg s-1 cm-2) and effective temperature (4577+/-60 K). We then determined the star's mass (5.6+/-1.7 M_Sun) using our new values with stellar oscillation results from Baudin et al. Finally, using the Yonsei-Yale evolutionary models, we estimated HR 2582's age to be 165 +20/-15 Myr. While our measurements do not provide the precision required to definitively state where the star is in its evolution, it remains an excellent test case for evaluating stellar interior models.