Clark, James; Larionov, V. M; Crowther, P. A.; Egan, M. P. and Arkharov, A.
Confirmation of the Luminous Blue Variable nature of AFGL 2298.
Astronomy and Astrophysics, 403
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We present new photometric and spectroscopic observations of the stellar source AFGL 2298 (= IRAS 18576+0341) that has recently been proposed as a candidate Luminous Blue Variable (LBV). Our data confirm that the star is a highly luminous B supergiant which is both spectroscopically and photometrically variable. Assuming a distance of 10 kpc, comparison of the 2001 June data to synthetic spectra suggest stellar parameters of T=12.5 kK, log(L/Lsun)=6.2 and dot M=5*E-5 Msun yr-1. Data obtained in 2002 August indicate an increase in both temperature (=15 kK) and mass loss rate (=1.2*E-4 Msun yr-1) at constant bolometric luminosity. These physical parameters place AFGL 2298 at the Humphreys-Davidson limit for the most luminous stars known. We conclude that the position of AFG 2298 in the HR diagram, the significant variability observed between 1999-2002 and presence of a massive ejection nebula are consistent with a classification of AFGL 2298 as a bona fide LBV.
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