Emission nebula | |
---|---|
H II region | |
Observation data: J2000 epoch | |
Right ascension | 23h 20m 48.3s [1] |
Declination | +61° 12′ 06″ [1] |
Distance | 7100 [2] to 11000 [3] [4] ly (3,400 pc) |
Apparent magnitude (V) | ~10 [5] |
Apparent dimensions (V) | 15′ × 8′ [6] |
Constellation | Cassiopeia |
Physical characteristics | |
Radius | 3 [2] to 5 [7] [4] ly |
Notable features | Shell around SAO 20575 [1] |
Designations | Bubble Nebula
[1] Sharpless 162 (Sh2-162) Caldwell 11 |
NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region [1] emission nebula in the constellation Cassiopeia. It lies close to the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7 [1] magnitude young central star, SAO 20575 ( BD+60°2522). [7] The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. [7] It was discovered in November 1787 by William Herschel. [5] The star BD+60°2522 is thought to have a mass of about 44 M☉.
With an 8-or-10-inch (200 or 250 mm) telescope, the nebula is visible as an extremely faint and large shell around the star. [6] [1] The nearby 7th magnitude star on the west hinders observation, but one can view the nebula using averted vision. [6] Using a 16-to-18-inch (410 to 460 mm) scope, one can see that the faint nebula is irregular, being elongated in the north south direction. [6]
Emission nebula | |
---|---|
H II region | |
Observation data: J2000 epoch | |
Right ascension | 23h 20m 48.3s [1] |
Declination | +61° 12′ 06″ [1] |
Distance | 7100 [2] to 11000 [3] [4] ly (3,400 pc) |
Apparent magnitude (V) | ~10 [5] |
Apparent dimensions (V) | 15′ × 8′ [6] |
Constellation | Cassiopeia |
Physical characteristics | |
Radius | 3 [2] to 5 [7] [4] ly |
Notable features | Shell around SAO 20575 [1] |
Designations | Bubble Nebula
[1] Sharpless 162 (Sh2-162) Caldwell 11 |
NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region [1] emission nebula in the constellation Cassiopeia. It lies close to the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7 [1] magnitude young central star, SAO 20575 ( BD+60°2522). [7] The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. [7] It was discovered in November 1787 by William Herschel. [5] The star BD+60°2522 is thought to have a mass of about 44 M☉.
With an 8-or-10-inch (200 or 250 mm) telescope, the nebula is visible as an extremely faint and large shell around the star. [6] [1] The nearby 7th magnitude star on the west hinders observation, but one can view the nebula using averted vision. [6] Using a 16-to-18-inch (410 to 460 mm) scope, one can see that the faint nebula is irregular, being elongated in the north south direction. [6]