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We present the results of optical spectroscopic observations of 54 candidate evolved massive stars revealed through the detection of mid-infrared nebulae of various shapes surrounding them with the {it Spitzer Space Telescope} and {it Wide-field Infrared Survey Explorer}. These observations, carried out with the Southern African Large Telescope (SALT) in 2010-2015, led to the discovery of about two dozens emission-line stars, of which 15 stars we classify as candidate luminous blue variables (cLBVs). Spectroscopic and photometric monitoring revealed significant changes in the spectra and brightness of four newly identified cLBVs, meaning that they are new members of the class of bona fide LBVs. We present an updated list of the Galactic bona fide LBVs. Currently, this list contains eighteen stars, of which more than 70 per cent are associated with circumstellar nebulae. We also discovered a very rare [WN] star - the central star of the planetary nebula Abell 48, and a WN3 star in a close, eccentric binary system with an O6V star in the Large Magellanic Cloud - the first-ever extragalactic massive star identified via detection of a circular shell around it. Most of the remaining targets are tentatively classified as OB, A and M stars.
Long-slit spectroscopy with the Southern African Large Telescope (SALT) of central stars of mid-infrared nebulae detected with the Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) led to the discovery of numerous candidate lumin
We present the first results from a study of TESS Sector 1 and 2 light curves for eight evolved massive stars in the LMC: six yellow supergiants (YSGs) and two luminous blue variables (LBVs), including S Doradus. We use an iterative prewhitening proc
We examine high-cadence space photometry taken by the Transiting Exoplanet Survey Satellite (TESS) of a sample of evolved massive stars (26 Wolf-Rayet stars and 8 Luminous Blue Variables or candidate LBVs). To avoid confusion problems, only stars wit
Determining the Galactic distribution and numbers of massive stars, such as Wolf-Rayet stars (WRs), is hampered by intervening Galactic or local circumstellar dust obscuration. In order to probe such regions of the Galaxy we can use infrared observat
Massive evolved stars can produce large amounts of dust, and far-infrared (IR) data are essential for determining the contribution of cold dust to the total dust mass. Using Herschel, we search for cold dust in three very dusty massive evolved stars