Wray 15-906 Low Mass Luminous Blue Variable on a Pre-Supernova Stage

Evolutionary link between Red Supergiants and Luminous Blue variables is interesting, but still poorly understood. Wepresent the results of study of the Galactic candidate luminous blue variable Wray 15-906, revealed via detection of itsinfrared circumstellar shell (of ≈ 2 pc in diameter) with the Wide-field Infrared Survey Explorer (WISE) and the HerschelSpace Observatory. Using the stellar atmosphere code CMFGEN and the Gaia parallax, we found that Wray 15-906 is arelatively low-luminosity, log(L/L ⊙ ) ≈ 5.4, star of temperature of 25 ± 2 kK. In the framework of single star evolution,the obtained results suggest that Wray 15-906 is a post-red supergiant star with initial mass of ≈ 25 M ⊙ and that beforeexploding as a supernova it could transform for a short time into a WN11h star. The presence of shell with mass 2.9±0.5 M ⊙indicates that Wray 15-906 has suffered substantial mass loss in the recent past.