Looking closer at the IRTF spectrum, there is perhaps some evidence for extreme mass loss. SiO lines at 4.0-4.3 μm usually appearing in absorption appear in emission, and the slope decreases dramatically at 4.5-5.0 μm while it usually stays roughly constant. A mass loss of 10^-4 Msol/yr or greater might be required to explain the observed spectral features.
For reference, I used Figure 4 in https://ui.adsabs.ha...A..76G/abstract.
Edited by VY Canis Majoris, 02 February 2023 - 04:25 AM.