IC 5146

IC 5146
Reflection nebula
emission nebula

Amateur image of IC 5146 "Cocoon Nebula"
Observation data: J2000 epoch
Right ascension 21h 53m 28.7s
Declination +47° 16′ 01″
Distance 3300 ly   (1000 pc)
Apparent magnitude (V) +7.2
Apparent dimensions (V) 12′
Constellation Cygnus
Designations Cocoon Nebula, Caldwell 19, Sh 2-125

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. The NGC description refers to IC 5146 as a cluster of 9.5 mag stars involved in a bright and dark nebula. The cluster is also known as Collinder 470.[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.

View of the IC 5146 star-forming region from ESA's Herschel Space Telescope

References

  1. 1 2 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.
  2. 1 2 Sanqunetti, Doug (2007). "IC 5146 - Cocoon Nebula". dougsastro.net. Retrieved 2008-08-06.
  3. ↑ O'Meara, Stephen James: The Caldwell Objects, Sky Publishing Corporation ISBN 0-933346-97-2 page 80
  4. 1 2 Pasachoff, Jay M. (2000). "Atlas of the Sky". Stars and Planets. New York, NY: Peterson Field Guides. p. 578. ISBN 0-395-93432-X.
  5. 1 2 Cannistra, Steve (2004). "Cocoon Nebula". starrywonders.com. Retrieved 2008-08-06.
  6. ↑ Nemiroff, R.; Bonnell, J., eds. (2002-10-14). "IC 5146: The Cocoon Nebula". Astronomy Picture of the Day. NASA. Retrieved 2008-08-06.

Coordinates: 21h 53m 32s, +47° 16′ 06″

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