IC 5146
| IC 5146 | |
|---|---|
|
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| Observation data | |
| Type | reflection/emission nebula |
| Right ascension | 21h 53m 28.7s |
| Declination | +47° 16′ 01″ |
| Distance | 3300 ly |
| Apparent magnitude (V) | +7.2 |
| Apparent dimensions (V) | 12′ |
| Constellation | Cygnus |
| Physical characteristics | |
| Other designations | Cocoon Nebula, Caldwell 19, Sh 2-125 |
| See also: Diffuse nebula, Lists of nebulae | |
IC 5146 (also Caldwell 19, Sh 2-125, and the Cocoon Nebula) is a reflection[1]/emission[2] nebula and Caldwell object in the constellation Cygnus. IC 5146 refers specifically to the star cluster and Sh2-125 to the nebula.[3] It shines at magnitude +10.0[4]/+9.3[2]/+7.2.[5] Its celestial coordinates are RA 21h 53.5m, dec+47° 16′. It is located near the naked-eye star Pi Cygni, the open cluster NGC 7209 in Lacerta, and the bright open cluster M39.[1][4] The cluster is about 4,000 ly away, and the central star that lights it formed about 100,000 years ago;[6] the nebula is about 12 arcmins across, which is equivalent to a span of 15 light years.[5] When viewing IC 5146, dark nebula Barnard 168 (B168) is an inseparable part of the experience, forming a dark lane that surrounds the cluster and projects westward forming the appearance of a trail behind the Cocoon.
[edit] References
- ^ a b Eicher, David J. (1988). The Universe from Your Backyard: A Guide to Deep-Sky Objects from Astronomy Magazine. AstroMedia (Kalmbach Publishing Company). ISBN 0-521-36299-7.
- ^ a b Sanqunetti, Doug (2007). "IC 5146 - Cocoon Nebula". dougsastro.net. http://dougsastro.net/IC-Catalog/ic5146.php. Retrieved 2008-08-06.
- ^ http://galaxymap.org/cgi-bin/sharpless.py?s=125
- ^ a b Pasachoff, Jay M. (2000). "Atlas of the Sky". Stars and Planets. New York, NY: Peterson Field Guides. pp. 578 pg. ISBN 0-395-93432-X.
- ^ a b Cannistra, Steve (2004). "Cocoon Nebula". starrywonders.com. http://www.starrywonders.com/cocoon.html. Retrieved 2008-08-06.
- ^ Nemiroff, Robert; Bonnell, Jerry (2002-10-14). "APOD: 2002 October 14 - IC 5146: The Cocoon Nebula". APOD (NASA). http://apod.nasa.gov/apod/ap021014.html. Retrieved 2008-08-06.
[edit] External links
- SEDS – IC 5146
- Simbad – IC 5146
- NED – IC 5146
- IC5146
- Sharpless Catalog 125
- IC 5146 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
Coordinates: 
21h 53m 32s, +47° 16′ 06″
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