Sh 2-185

Sh 2-185
Emission nebula
H II region
IC 59 (center) and IC 63 (left) near Gamma Cassiopeiae
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 ascension01h 00m 00s[1]
Declination+60° 59′[1]
Distance10,500 ± 2,100[2] ly
Apparent dimensions (V)2°[3]
ConstellationCassiopeia
See also: Lists of nebulae

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.[3] Sh 2-185 is located at a distance of approximately 10,500 ly (3.23 kpc) from the Sun.[2] The region is surrounded by a dust shell,[4] and displays several infrared point sources that are a characteristics of young stellar objects.[5]

This H II region includes the reflection and emission nebulae IC 59 and IC 63.[4] Both nebulae have a cometary shape, with IC 63 being the brighter of the two.[6] 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.[5] The nebulae are the closest photodissociation regions to the Sun.[6]

  1. ^ a b Cite error: The named reference Dubout-Crillon_1976 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Foster_Brunt_2015 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Sharpless_1959 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Soam_et_al_2021 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Karr_et_al_2005 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Eiermann_et_al_2024 was invoked but never defined (see the help page).