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We present the results of studying the spectral and photometric variability of the luminous blue variable star V 532 in M 33.The photometric variations are traced from 1960 to 2010, spectral variations from 1992 to 2009. The star has revealed an absolute maximum of visual brightness (1992)(1993)(1994), high/cold state) and an absolute minimum (2007-2008, low/hot state) with a brightness difference of ∆B ≈ 2.3 m . The temperature estimates in the absolute maximum and absolute minimum were found to be T ∼ 22000 K and T ∼ 42000 K, respectively. The variability of the spectrum of V 532 is fully consistent with the temperature variations in its photosphere, while both permitted and forbidden lines are formed in an extended stellar atmosphere. Broad components of the brightest lines were found, the broadening of these components is due to electron scattering in the wind parts closest to the photosphere. We measured the wind velocity as a difference between the emission and absorption peaks in the P Cyg type profiles. The wind velocity clearly depends on the size of the stellar photosphere or on the visual brightness, when brightness declines, the wind velocity increases. In the absolute minimum a kinematic profile of the V 532 atmosphere was detected. The wind velocity increases and its temperature declines with distance from the star. In the low/hot state, the spectral type of the star corresponds to WN8.5h, in the high/cold state to WN11. We studied the evolution of V 532 along with the evolution of AG Car and the massive WR binary HD 5980 in SMC. During their visual minima, all the three stars perfectly fit with the WNL star sequence by Crowther and Smith (1997).However, when visual brightness increases, all the three stars form a separate sequence. It is possible that this reflects a new property of LBV stars, namely, in the high/cold states they do not pertain to the bona fide WNL stars.

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We report the discovery of a new Galactic candidate luminous blue variable (cLBV) via detection of an infrared circular nebula and follow‐up spectroscopy of its central star. The nebula, MN112, is one of many dozens of circular nebulae detected at 24 μm in the Spitzer Space Telescope archival data, whose morphology is similar to that of nebulae associated with known (c)LBVs and related evolved massive stars. Specifically, the core‐halo morphology of MN112 bears a striking resemblance to the circumstellar nebula associated with the Galactic cLBV GAL 079.29+00.46, which suggests that both nebulae might have a similar origin and that the central star of MN112 is an LBV. The spectroscopy of the central star showed that its spectrum is almost identical to that of the bona fide LBV P Cygni, which also supports the LBV classification of the object. To further constrain the nature of MN112, we searched for signatures of possible high‐amplitude (≳1 mag) photometric variability of the central star using archival and newly obtained photometric data covering a 45‐yr period. We found that the B magnitude of the star was constant within error margins, while in the I band the star brightened by ≃0.4 mag during the last 17 yr. Although the non‐detection of large photometric variability leads us to use the prefix ‘candidate’ in the classification of MN112, we remind the readers that the long‐term photometric stability is not unusual for genuine LBVs and that the brightness of P Cygni remained relatively stable during the last three centuries.

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