The adjacent HII regions Sh 2-152 and Sh 2-153 appear to be physically related with Sh 2-153 being the larger and fainter nebula in the image and a major source of the ionising radiation being located in the brighter Sh 2-152 in an unnamed O9V star.
Avedisova combines Sh 2-152 and Sh 2-153 into the star formation region
SFR 108.78-0.94, which also contains 7 masers including well studied ones such as
V* V627 Cas and
SH 2-152 SE.
Sh 2-152 and Sh 2-153 form one of the two cores of the 105 thousand solar mass molecular cloud
[UUT2000] Cloud A. (The other core is associated with Sh 2-147, Sh 2-148, and Sh 2-149.) This molecular cloud may be interacting with the supernova remnant
SNR G109.1-01.0 (CTB 109).
According to Russeil, the ionising star for Sh 2-152 lies at a distance of 2390 +/-210 parsecs and this is likely the distance for Sh 2-153 as well.[
1] This suggests that this nebula (and likely the entire molecular cloud complex it is part of) may have the same distance and direction as the dusty
Cas OB2 association.
The adjacent HII regions Sh 2-152 and Sh 2-153 appear to be physically related, with a major source of the ionising radiation being located in Sh 2-152 in an unnamed O9V star.[
2]
Notes
1. ^ Russeil, D., Adami, C., & Georgelin, Y. M. (2007). "Revised distances of
Northern HII regions", Astronomy and Astrophysics, Vol. 470, 161-171.
[2007A&A...470..161R]
2. ^ Pismis, P. & Hasse, I. (1980). "Internal motions in H II regions. VIII -
The nebular complex S152-S153", Revista Mexicana de Astronomia y
Astrofisica, Vol. 5, 39-44. [1980RMxAA...5...39P]