Sh 2-185
| Emission nebula | |
|---|---|
| H II region | |
The brightest star is Gamma Cassiopeiae. The blue IC 59 nebula is positioned above the star and the redder IC 63 is to the left. | |
| Observation data: J2000 epoch | |
| Right ascension | 01h 00m 00s |
| Declination | +60° 59′ |
| Distance | 10,500 ± 2,100 ly |
| Apparent dimensions (V) | 2° |
| Constellation | Cassiopeia |
Sh 2-185 is an H II region centered on the massive star system Gamma Cassiopeiae (γ Cas) in the northern constellation of Cassiopeia. It was included in the second Catalogue of H II Regions, published in 1959 by Stewart Sharpless. Sh 2-185 is located at a distance of approximately 10,500 ly (3.23 kpc) from the Sun. The region is surrounded by a dust shell, and displays several infrared point sources that are a characteristics of young stellar objects.
This H II region includes the reflection and emission nebulae IC 59 and IC 63. Both nebulae have a cometary shape, with IC 63 being the brighter of the two. The difference in appearance between the two nebulae is a consequence of their physical distance from γ Cas. IC 63 displays a well-defined ionization front, while this is lacking in IC 59. The nebulae are the closest photodissociation regions to the Sun.