Characterization of the Red Giant HR 2582 Using the CHARA Array

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 _⊙), luminosity (517.8 ± 17.5 L _⊙), bolometric flux (14.8 ± 0.5 × 10^-8 erg s^-1 cm^-2), and effective temperature (4577 ± 60 K). We then determined the star's mass (5.6 ± 1.7 M _⊙) 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.