Sh 2-159 appears to be ionised by the O9.5 class emission star
[MO2001] 82.
Russeil combines Sh 2-158 and Sh 2-159 into one star formation region. You can see the two nebulae embedded in the 595 thousand solar mass dust cloud
[UUT2000] Cloud G in
this MSX infrared image.
All of these objects are part of the dusty
Cas OB2 association.
A wide area image that includes Sh 2-159 can be seen
here.
Russeil identifies an O9 V class ionising star for Sh 2-159. [
1] She gives no catalog designation and neither SIMBAD nor the Reed catalog lists a star at the exact location she provides. However, SIMBAD does list a nearby O9.5 class emission star
[MO2001] 82 and Avedisova includes both Sh 2-159 and this emission star in star formation region
111.64+0.37.
Both Sh 2-158 (NGC 7538) and Sh 2-159 are embedded in the same molecular cloud complex.[
2]
Both Sh 2-158 and Sh 2-159 are embedded in the 595 thousand solar mass molecular cloud [UUT2000] Cloud G. This cloud is surrounded by the much larger diffuse nebula Sh 2-161B. [
3]
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. ^ Read, P. L. (1980). "H I aperture synthesis observations towards galactic
H II regions and molecular clouds. I - NGC 7538 and S 159", Monthly Notices
of the Royal Astronomical Society, Vol. 192, 11-32. [1980MNRAS.192...11R]
3. ^ Ungerechts, H., Umbanhowar, P., & Thaddeus, P. (2000). "A CO Survey of
Giant Molecular Clouds near Cassiopeia A and NGC 7538", The Astrophysical
Journal, Vol. 537, 221-235. [2000ApJ...537..221U]