2021/11/01 by Xuepeng Chen, Weihua Guo, Li Sun +10
Physics and Astronomy · #Acceleration #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Galaxy #Gamma ray #Interstellar medium #Physics #Scientific Research and Discoveries #Stars #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.3847/1538-4357/ac2507
21 pages, 7 figures, to be published by the ApJ
arxiv created 2021/11/01 · openalex publication_date 2021/11/01 · arxiv updated 2021/12/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present wide-field multi-wavelength observations of γ Cassiopeiae (or γ~Cas for short) in order to study its feedback toward the interstellar environment. A large expanding cavity is discovered toward γ~Cas in the neutral hydrogen (HI) images at a systemic velocity of about -10 km/s. The measured dimension of the cavity is roughly 2.0 deg × 1.4 deg (or 6.0 pc × 4.2 pc at a distance of 168 pc), while the expansion velocity is about 5.0±0.5 km/s. The CO observations reveal systematic velocity gradients in IC63 (about 20 km/s/pc) and IC59 (about 30 km/s/pc), two cometary globules illuminated by γ~Cas, proving fast acceleration of the globules under stellar radiation pressure. The gas kinematics indicate that the cavity is opened by strong stellar wind, which has high potential to lead to the peculiar X-ray emission observed in γ~Cas. Our result favors a recent new scenario that emphasizes the roles of stellar wind and binarity in the X-ray emission of the γ~Cas stars.