An HI interstellar bubble linked to the O-type stars BD +24°3866 and BD +25°3952

Abstract

We investigate the ISM in the vicinity of the O-type stars BD +24°3866 (O8.5II(f)), BD +24°3881 (O6.5III(f)) and BD +24°3952 (O8) based on radio continuum and HI line data obtained with the Synthesis Telescope of the Dominion Radio Astrophysical Observatory (DRAO) with synthesized beams of 1′.5 and 7′ at 1420 and 408 MHz, respectively. High angular resolution <i>IRAS</i> data (<i>HIRES</i>) are also analyzed. BD +24°3866 is found to be located close to the inner border of a slowly expanding shell. The evolved HII region Sh2-88, which is excited by BD +25°3952, appears to be interacting with neutral material in the approaching part of this shell. The whole structure is ata distance of 2.4 kpc and is about 23×15 pc in radius. The total swept up mass is 1300 M⊙. The stellar winds of BD +24°3866 and BD +25°3952, are mainly responsible for shaping the HI structure. An HI expanding shell was also found to be related to the HII region G61.7+0.9. At a kinematic distance of 2.4 kpc, this feature is 10 pc in radius and has neutral and ionized masses of 200 and 135 M⊙, respectively. The present observational data do not allow us to identify a definite interstellar HI feature associated with BD +24°3881. We consider different explanations for this fact.