Astronomy and Astrophysics – Astronomy
Scientific paper
Jun 2006
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006rmxac..26..166v&link_type=abstract
XI IAU Regional Latin American Meeting of Astronomy (Eds. L. Infante & M. Rubio) Revista Mexicana de Astronomía y Astrofísica (S
Astronomy and Astrophysics
Astronomy
Scientific paper
We analyze the distribution of the gas and dust in the environs of the northern part of the HII region Sh2-157. We based our study on radio continuum and neutral hydrogen observations obtained using the Synthesis Telescope of the DRAO (Canada), CO data from the Five College Radio Astronomy Observatory (USA), and IRAS (HIRES) data. The northern part of the HII region, SG13, is a ring nebula related to WR157, belonging to the open cluster Ma 50, which is projected close to the center of SG 13. The nebula is clearly detected in the radio continuum at 1420 and 408 MHz showing a thermal spectrum. The CO emission distribution reveals two concentrics shells associated with SG13 of ˜ 25' and 50' in diameter, detected within the velocity interval -52 to -41 km s^{-1}. The HI line emision distribution shows a low emission region present within the velocity range -47 to -34 km s^{-1}, which correlates with the higher galactic latitude section of the outer CO shell.
Assuming circular galactic rotation models, the radial velocity of the ionized gas (-53 to -33 km s^{-1}, Lozinskaya et al. 1986, Ap&SS, 121, 357) and the CO gas (-47.6 km/s), indicate a kinematical distance d_{kin} = 4.2+/-0.9 kpc. This value coincides, within errors, with the spectrophotometric distance estimate of WR 157 and Ma 50, suggesting that the neutral structures detected in HI and CO are associated with this open cluster. We can explain the distribution of the interstellar material in the environs of WR 157 and Ma 50 by considering that SG 13 and its neutral gas and dust counterparts have been swept up by the stellar winds of the WR star. We believe that the outer CO shell and HI structure originated during previous evolutionary stages of the WR star.
Cappa Cristina E.
Pineault Serge
Vasquez Javier
No associations
LandOfFree
The complex ISM towards the HII region Sh2-157 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The complex ISM towards the HII region Sh2-157, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The complex ISM towards the HII region Sh2-157 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1478878