MN112: a new Galactic candidate Luminous Blue Variable - Astrophysics > Solar and Stellar AstrophysicsReport as inadecuate

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Abstract: We report the discovery of a new Galactic candidate Luminous Blue VariablecLBV via detection of an infrared circular nebula and follow-up spectroscopyof its central star. The nebula, MN112, is one of many dozens of circularnebulae detected at $24 \mu$m in the {\it Spitzer Space Telescope} archivaldata, whose morphology is similar to that of nebulae associated with knowncLBVs and related evolved massive stars. Specifically, the core-halomorphology of MN112 bears a striking resemblance to the circumstellar nebulaassociated with the Galactic cLBV GAL 079.29+00.46, which suggests that bothnebulae might have a similar origin and that the central star of MN112 is aLBV. The spectroscopy of the central star showed that its spectrum is almostidentical to that of the bona fide LBV P Cygni, which also supports the LBVclassification of the object. To further constrain the nature of MN112, wesearched for signatures of possible high-amplitude $\ga 1$ mag photometricvariability of the central star using archival and newly obtained photometricdata covering a 45 year period. We found that the B magnitude of the star wasconstant $\simeq$ 17.1$\pm$0.3 mag over this period, while in the I band thestar brightened by $\simeq 0.4$ mag during the last 17 years. Although thenon-detection of large photometric variability leads us to use the prefix`candidate- in the classification of MN112, we remind that the long-termphotometric stability is not unusual for genuine LBVs and that the brightnessof P Cygni remains relatively stable during the last three centuries.

Author: V.V.Gvaramadze, A.Y. Kniazev, S. Fabrika, O. Sholukhova, L.N. Berdnikov, A.M. Cherepashchuk, A.V. Zharova


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