The HII region NGC 6357, also called W 22 or the War and Peace Nebula, is ionised by the Pismis 24
and AH03 J1725−34.4
star clusters. Pismis 24 includes the multiple O4 and O4-5 star system [N78] 35
according to a 1984 paper. (SIMBAD gives a cooler O7 III class for this star.)
Near by is the Wolf-Rayet star WR 93
, which is also a multiple star system with a class O7-9 companion.
The Cat's Paw nebula NGC 6334 lies at approximately the same distance and is separated from it by a dark cloud. You can see both nebulae together
in this image.
An amazing closeup of part of this nebula can be seen in this Hubble image
Contains the star cluster Pismis 24 which includes a multiple O4 and O4-5 star system. Near by is the Wolf-Rayet star WR 93, which is also a multiple star system with a class O7-9 companion.[1
At the same distance as NGC 6334 and separated from it by a dark cloud.[2
The RCW catalog divides NGC 6357 into four subnebulae: RCW 131a-d.
Bica et.al. report two infrared clusters [BDS2003] 100
and [BDS2003] 101
within RCW 131b = G353.1+0.7, which is the region of the nebula immediately surrounding Pismis 24. [3
1. ^ Lortet, M. C., Testor, G., & Niemela, V. (1984). "Optical study of the
galactic nebula NGC 6357 and of its stellar content, Pis 24 and the WC 6
star HD 157504", Astronomy and Astrophysics, Vol. 140, 24-32.
2. ^ Neckel, T. (1984). "Polarimetric and new photometric observations in the
NGC6334/6357 region", Astronomy and Astrophysics, Vol. 137, 58-62.
3. ^ Bica, E., Dutra, C. M., Soares, J., et al. (2003). "New infrared star
clusters in the Northern and Equatorial Milky Way with 2MASS", Astronomy
and Astrophysics, Vol. 404, 223-232. [2003A&A...404..223B]