An H I interstellar bubble linked to the O-type stars BD +24or 3866 and BD +25or 3952

CAPPA CRISTINA E.; PINEAULT SERGE; ARNAL E. MARCELO; CICHOWOLSKI SILVINA

ASTRONOMY AND ASTROPHYSICS

Año: 2002 vol. 395 p. 955 - 967

0004-6361

We investigate the ISM in the vicinity of the O-type stars BD +24or 3866 (O8.5II(f)), BD +24or 3881 (O6.5III(f)) and BD +24or 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\farcm 5 and 7\arcmin at 1420 and 408 MHz, respectively. High angular resolution IRAS data (HIRES) are also analyzed. BD +24or 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 +25or 3952, appears to be interacting with neutral material in the approaching part of this shell. The whole structure is at a distance of 2.4 kpc and is about 23x15 pc in radius. The total swept up mass is 1300 Msun. The stellar winds of BD +24or 3866 and BD +25or 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 Msun, respectively. The present observational data do not allow us to identify a definite interstellar HI feature associated with BD +24or 3881. We consider different explanations for this fact.