2013ApJ...772...16B

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±0.5x10^–8 erg/s/cm2), 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_–15⁺²⁰ 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.