Sh2 185
Ghost of Cassiopeia
The Ghost of Cassiopeia, officially designated as IC 63, is a faint and ethereal nebula located approximately 550 to 600 light-years from Earth in the northern constellation of Cassiopeia. It is primarily known for its wispy, spectral appearance, often described as a hooded figure with outstretched arms.
The Ghostly Pair: IC 63 is often associated with a neighbouring, even fainter nebula called IC 59. Together, they form part of a larger nebulous region known as Sharpless 2-185.
Influence of Gamma Cassiopeiae: The nebula is being sculpted and slowly eroded by intense radiation and stellar winds from Gamma Cassiopeiae (also known as Navi), a massive blue-white giant star located only 3 to 4 light-years away. Navi is roughly 19 times more massive and 65,000 times brighter than the Sun.
Key Characteristics
Distance:
While some sources like Wikipedia list a distance of approximately 10,500 light-years, more recent measurements cited by Telescope Live and Hipparcos place the nebula and its central star much closer, at roughly 550 to 613 light-years from Earth.
Dimensions:
The entire nebular structure spans roughly 10 light-years across.
Temperature:
Spectral measurements reported by Telescope Live indicate that IC 59 is slightly cooler (590K) and less dense than IC 63 (630K).
Illuminating Star:
Gamma Cassiopeiae is a massive subgiant (spectral type B0.5 IVe) with roughly 17 times the mass of the Sun and 34,000 times its luminosity.