First detection of doubly deuterated methyl acetylene (CHD2CCH and CH2DCCD) M. Agúndez, E. Roueff, C. Cabezas, J. Cernicharo and N. Marcelino A&A, 649 (2021) A171 Published online: 01 June 2021 DOI: 10.1051/0004-6361/202140843