Much of this nebula, located within the
Vela molecular ridge, is obscured by dust. Star formation is taking place at the ionisation front, driven by the O9 Ib supergiant Herb 25 A =
VDBH 25 according to Avedisova. She places RCW 34 in star formation region
SFR 264.28+1.43 along with 3 masers and the reflection nebulae
Bran 206A-D.
RCW 34 includes the infrared star cluster
[DBS2003] 28.
Oddly, Herb 25 A appears to be listed in SIMBAD twice. The second duplicate entry is under
VdBH 25a.
You can see a good
Spitzer infrared image here.
"RCW 34 is a cometary shaped HII region, located at 3.1 kpc and excited by an O9Ib star (Russeil et al. 2003, Avedisova & Kondratenko 1984). MSX Band A emission surrounds the ionized region with a bright MSX and IRAS point source located just in front of the bright ionization front. Near-IR observations indicate that star formation is observed at the border of the ionization front (Zavagno et al. in preparation)."[
1]
A 2010 Spitzer paper has a good overview. This paper reduces the class of the main ionising star to O8.5 V and identifies two additional B0.5 V and B3 V ionising stars. [
2]
Notes
1. ^ Deharveng, L., Zavagno, A., & Caplan, J. (2005). "Triggered massive-star
formation on the borders of Galactic H II regions. I. A search for
``collect and collapse'' candidates", Astronomy and Astrophysics, Vol.
433, 565-577. [2005A&A...433..565D]
2. ^ Bik, A., Puga, E., Waters, L. B. F. M., et al. (2010). "Sequential Star
Formation in RCW 34: A Spectroscopic Census of the Stellar Content of
High-Mass Star-Forming Regions", The Astrophysical Journal, Vol. 713,
883-899. [2010ApJ...713..883B]