My backfocus was off, but I kind of like it regardless.
The Cocoon Nebula (IC 5146) is a reflection/emission nebula located approximately 2,500 light-years away in the constellation
Cygnus. With an apparent magnitude of 7.2 and an apparent size of 12 arcminutes, it can be observed in amateur telescopes. Also catalogued as Sh 2-125 and Caldwell 19, the nebula is an active star-forming region associated with the young open cluster Collinder 470.The Cocoon Nebula is illuminated by BD +46°3474, a hot young main sequence star of the spectral type B0 V or B1 V. The star is enveloped in a molecular cloud at the eastern end of a dark lane spanning 2 degrees. It was reported to be a close binary system in 1987 and may even be a multiple-star system. A 2002
study identified it as the most massive member of IC 5146. The star has a mass of 14 ± 4 solar masses and is believed to be only 100,000 years old.One of the star’s neighbours, catalogued as BD +46°3471, has been identified as a HAeBe variable. HAeBe (Herbig Ae/Be) stars are A- and B-type pre-main sequence stars that are still embedded in clouds of dust and gas and may have circumstellar disks. They show variability in brightness due to planetesimals in the circumstellar disks. BD +46°3471 lies about 10 arcminutes west of BD +46°3474. Both stars are surrounded by clusters of young stars. The estimated median age of these stars is around 1 million years.The shape of the Cocoon Nebula has been explained as the result of BD +46°3474 having formed near the surface of the cloud and carved a cavity out of which nebular material is flowing in our direction.The western part of the nebula is intersected by a dark lane that winds around the young cluster. The dark nebula is catalogued as Barnard 168 (B168). It stretches from the Cocoon Nebula in the direction of the bright open cluster
Messier 39.
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