Confirmation of the star J004229.87+410551.8 in M31 as a B[e] supergiant

Sarkisyan A., Vinokurov A., Solovyeva Yu., Atapin K., Sholukhova O., Fabrika S., Bizyaev D

Published 2022-10-24Version 1

We study the luminous blue variable candidate J004229.87+410551.8 in the Andromeda Galaxy. Earlier, the star displayed a spectral anomaly: although a hot emission spectrum had been detected, it had strong CaII H and K absorption lines. Subsequently the star was assumed to be a hot hypergiant or a B[e] supergiant. For the purpose of clear star classification, we conducted spectroscopic and photometric analysis of the object and its surroundings with the 6-m telescope of SAO RAS, the 3.5-m ARC telescope of the Apache Point Observatory and the 2.5-m telescope of the Caucasus Mountain Observatory of the Sternberg Astronomical Institute. The spectrum of the star has the FeII, [FeII], [OI], and Balmer emission lines. Its spectral energy distribution shows an excess in the near-infrared range due to hot circumstellar dust. The indicated features and a high estimated value of star's luminosity ($\log (L/L_{\odot}) = 4.6\pm 0.2$) allow us to finally classify the object as a B[e] supergiant.