Evidence of Increased Macroturbulence for Betelgeuse during Great Dimming

Abstract We compared high-resolution spectra of Betelgeuse observed before and during the Great Dimming. Atomic lines are shallow and broad during the Great Dimming presumably because of molecular veiling and increased macroturbulence, ν macro ≳ 23 km s−1. The best fit for TiO bands was found for the MARCS model atmosphere with T eff = 3500 K.