NGC 7635
| Emission nebula | Lists of nebulae |
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| Observation data (Epoch J2000) |
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| Type | Emission[1] |
| Right ascension | 23h 20m 48.3s[2] |
| Declination | +61° 12′ 06″[2] |
| Distance | 11 kly (3.4 kpc) (7100[3] to 11000[4][5] ly, sources differ) |
| Apparent magnitude (V) | ~10[6] |
| Apparent dimensions (V) | 15′ × 8′[1] |
| Constellation | Cassiopeia |
| Physical characteristics | |
| Radius | 5 ly (3[3] to 5,[5][7] sources differ) |
| Absolute magnitude (V) | Unknown |
| Notable features | Shell around SAO 20575[2] |
| Other designations | Bubble Nebula[2] Sharpless 162 (Sh2-162) Caldwell 11 |
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NGC 7635, also called the Bubble Nebula, Sharpless 162, or Caldwell 11, is a H II region[2] emission nebula in the constellation Cassiopeia. It lies close to the direction of the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7[2] magnitude young central star, the 15 ± 5 M☉[4] 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 1787 by William Herschel.[6] The star SAO 20575 or BD+602522 is thought to have a mass of 10-40 Solar masses.
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Amateur observation [edit]
With an 8 or 10-inch (250 mm) telescope, the nebula is visible as an extremely faint and large shell around the star.[1][2] The nearby 7th magnitude star on the west hinders observation, but one can view the nebula using averted vision.[1] Using a 16 to 18-inch (460 mm) scope, one can see that the faint nebula is irregular, being elongated in the north south direction.[1]
Notes [edit]
- ^ a b c d e Kepple & Sanner 1998
- ^ a b c d e f g SIMBAD 2007
- ^ a b Hubble Site, 2000. An Expanding Bubble in Space. "diameter of 6 light-years", "distance of 7,100 light-years".
- ^ a b APOD (July 16, 2004), Astronomy Picture of the Day: The Bubble, NASA
- ^ a b APOD (October 18, 2006), Astronomy Picture of the Day: NGC 7635: The Bubble, NASA
- ^ a b "NGC-IC Project Database". Retrieved 2008-12-15.
- ^ a b c APOD (November 7, 2005), Astronomy Picture of the Day: NGC 7635: The Bubble Nebula, NASA
References [edit]
- Kepple, George Robert; Sanner, Glen W. (1998), The Night Sky Observer's Guide 1, Willmann-Bell, Inc., pp. 108–109, ISBN 0-943396-58-1
External links [edit]
- SIMBAD (February 23, 2007), Results for NGC 7635, SIMBAD, Centre de Données Astronomiques de Strasbourg
- NGC7635 The Bubble Nebula
- NGC 7635 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
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