Sh 2-305 is ionised by at least two O-class stars (
[VM75] Sh 2-305 4 (O8.5 V) and
[VM75] Sh 2-305 2 (O9.5 V)), and possibly two B0 class stars as well. It contains the loose infrared cluster
[DBS2003] 5.
Avedisova places this nebula in star formation region
SFR 233.75-0.18 along with 5 infrared sources, a water maser and the star cluster
Mayer 3.
A 1995 paper places Sh 2-299, Sh 2-300, Sh 2-305, Sh 2-306, Sh 2-307 and Sh 2-309 into the same giant molecular cloud complex. A 1996 paper places Sh 2-305 to Sh 2-309 into molecular cloud
[JKK96] D within the enormous infrared ring called the
GS234-02 supershell, in the Perseus arm.
You can view the enormous dust ring around the supershell in this
WISE infrared image. Sh 2-299 and Sh 2-300 also appear in this direction.
Sh 2-305 is part of a huge molecular cloud complex with a distance of 4200 pc. There may be at least four exciting stars for this region: VM 4 (O8.5 V),VM 2 (O9.5 V), VM 7 (B0 V), VM 8 (B0 V). However, VM 7 and VM 8 are doubtful. [
1]
More on the GS234-02 supershell. [
2]
Contains the star cluster [DBS2003] 5. [
3]
Notes
1. ^ Russeil, D., Georgelin, Y. M., Georgelin, Y. P., et al. (1995). "Galactic
HII regions at l= 234deg.", Astronomy and Astrophysics Supplement Series,
Vol. 114, 557. [1995A&AS..114..557R]
2. ^ Jung, Jae Hoon, Koo, Bon-Chul, & Kang, Yong-Hee (1996). "GS234-02: A Star
Forming Supershell in the Outer Galaxy", The Astronomical Journal, Vol.
112, 1625. [1996AJ....112.1625J]
3. ^ Dutra, C. M., Bica, E., Soares, J., et al. (2003). "New infrared star
clusters in the southern Milky Way with 2MASS", Astronomy and Astrophysics,
Vol. 400, 533-539. [2003A&A...400..533D]