The nature of VX Sagitarii - Is it a TŻO, a RSG, or a high-mass AGB star? H. M. Tabernero, R. Dorda, I. Negueruela and E. Marfil A&A, 646 (2021) A98 Published online: 16 February 2021 DOI: 10.1051/0004-6361/202039236