Optically thin circumstellar medium in the β Lyr A system M. Brož, D. Mourard, J. Budaj, P. Harmanec, H. Schmitt, I. Tallon-Bosc, D. Bonneau, H. Božić, D. Gies and M. Šlechta A&A, 645 (2021) A51 Published online: 08 January 2021 DOI: 10.1051/0004-6361/202039035