WS1: one more new Galactic bona fide luminous blue variable

Abstract

In this Letter, we report the results of spectroscopic and photometric monitoring of the candidate luminous blue variable (LBV) WS1, which was discovered in 2011 through the detection of a mid-infrared circular shell and follow-up optical spectroscopy of its central star. Our monitoring showed that WS1 brightened in the B, V and I bands by more than 1 mag during the last three years, while its spectrum revealed dramatic changes during the same time period, indicating that the star became much cooler. The light curve of WS1 demonstrates that the brightness of this star has reached maximum in 2013 December and then starts to decline. These findings unambiguously proved the LBV nature of WS1 and added one more member to the class of Galactic bona fide LBVs, bringing their number to sixteen (an updated census of these objects is provided).

5 pages, 3 figures, accepted for publication in MNRAS Letters

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Cited by in corpus (5)

• Optical spectroscopy of the blue supergiant Sk-69 279 and its circumstellar shell with SALT
• New luminous blue variable candidates in the NGC 247 galaxy
• A deep near-infrared spectroscopic survey of the Scutum-Crux arm for Wolf-Rayet stars
• Monitoring broad emission-line components in spectra of the two low-metallicity dwarf compact star-forming galaxies SBS 1420+540 and J1444+4840
• Wray 15-906: a candidate luminous blue variable discovered with WISE, Herschel and SALT