This HII region is ionised by the O8 V star
HD 161853 and is part of the Sh 2-15 to Sh 2-20 complex of HII regions located in the
Sgr OB5 association in the Sagittarius arm. It is the location of the radio source
W25.
Avedisova places it in star formation region
SFR 358.44-1.88 with 2 masers and the star cluster
VDBH 249. (However, SIMBAD identifies VDBH 249 as a globular cluster.)
Sh 2-15 is also called W25, Gum 69, or RCW 134. [
1]
Also called RCW 134, this HII region is at a distance of 1600 pc and ionised by the O8 V star HD 161853. [
2]
Although distance estimates place Sh 2-15 at approximately the same distance as Sh 2-16 to Sh 2-20, it is brighter and located further below the galactic plane than the other nebulae.
Notes
1. ^ Gray, A. D. (1994). "The Most Galactic Center Survey - Part Two - New
Results on Published Supernova Remnants and G:2.4+1.4", Monthly Notices of
the Royal Astronomical Society, Vol. 270, 835. [1994MNRAS.270..835G]
2. ^ Yamaguchi, Reiko, Saito, Hiro, Mizuno, Norikazu, et al. (1999). "Molecular
Clouds and Star Formation in the Southern H II Regions", Publications of
the Astronomical Society of Japan, Vol. 51, 791-818. [1999PASJ...51..791Y]