A Parsec-scale Circumstellar Shell Around VX Sgr: Mass Loss and RSG/T.ZO Nature
The study discovered a thin, arc-shaped shell around VX Sagittarii (VX Sgr), suggesting it is photoionized circumstellar material from past RSG wind rather than a bow shock. This observation constrains VX Sgr to be an RSG/RHG, not a super-AGB star. The mass-loss rate is estimated at approximately 4 x 10^-5 M⊙ yr^-1, and future spectroscopic tests are needed to distinguish between RSG and Thorne–Zytkow Object (TZO) candidates.