Optical observations of the Galactic supernova remnant HB9 and H II region G159.2+3.3 Jiang-Tao Li, Li-Yuan Lu, Huiyang Mao, Zi-Qing Xia, Yang Chen, Ping Zhou and Xin Zhou A&A, 690 (2024) A42 Published online: 26 September 2024 DOI: 10.1051/0004-6361/202451595