On the nature of VX Sagitarii: Is it a TZO, a RSG or a high-mass AGB star?.
On the nature of VX Sagitarii: Is it a TZO, a RSG or a high-mass AGB star?.
Aims. We present a spectroscopic analysis of the extremely luminous red star VX Sgr based on high-resolution observations combined with AAVSO light curve data. Given the puzzling characteristics of VX Sgr, we explore three scenarios for its nature: a massive red supergiant (RSG) or hypergiant (RHG), a Thorne Zytkow object …