Sh 2-82

Last updated

Sharpless 2-82
Nebula
Sh2-82, Cocoon Nebula (noao-sh2-82).jpg
Image of Sh 2-82 Nebula
Observation data: epoch
Right ascension 19h 30m 14.90s [1]
Declination +18° 17′ 30.0″ [1]
Distance3,500  ly    (1,100  pc)
Constellation Sagitta
DesignationsSh 2-82, LBN 129, DG 159 [1]
See also: Lists of nebulae

Sh 2-82 (also known as the Little Cocoon Nebula or Little Trifid Nebula) is a small H II region and reflection nebula located in the constellation Sagitta. It is an active star-forming region embedded within a dark nebula, featuring a bright red emission component ionized by ultraviolet radiation from a hot young star, contrasted against a hazy blue reflection nebula created by scattered starlight. The nebula's compact, cocoon-like structure, with a flare on one side, makes it a popular target for amateur astronomers and astrophotographers. [2] [3] The nebula is ionized by the star HD 231616 (B0.5III). [4] [5] [6]

Contents

Observation and characteristics

The nebula has some informal nicknames, such as Little Cocoon Nebula, which derives from its enveloping reflection component resembling a protective shell around the central emission core, similar to the IC 5146 (Cocoon Nebula), while Little Trifid Nebula draws a comparison to the larger Trifid Nebula (M20) due to its tripartite appearance in deep-sky images, blending emission, reflection, and dark nebula. [7] [8]

Sharpless 2-82 is situated near the inner edge of the Vulpecula OB4 stellar association, a group of young, hot stars in the Milky Way's Sagittarius arm. It lies approximately 3,500 light-years from Earth. Astrophotography of Sharpless 2-82 often employs hydrogen-alpha and O-III narrowband imaging to highlight the ionized gas structures, revealing intricate dust lanes and embedded young stellar objects (YSOs). [9] [4]

The primary ionizing source is the blue giant star HD 231616 (B0.5III), part of the OB association Vul 0B4, and surrounding the emission nebula is a bluish reflection component, formed when light from nearby stars scatters off dust grains in the foreground dark cloud LDN 727. [10] This creates a hazy halo that flares asymmetrically on one side, giving the cocoon appearance. [9]

See Also

References

  1. 1 2 3 "Simbad - Object view". simbad.cds.unistra.fr. Retrieved 2025-11-16.
  2. ↑ info@noirlab.edu. "Sh2-82, Cocoon Nebula". www.noirlab.edu. Retrieved 2025-11-16.
  3. ↑ svenarnold (2024-10-21). "Sh2-82 – Little Cocoon Nebula – Astrophotography". svenarnold.com (in Swiss High German). Retrieved 2025-11-16.
  4. 1 2 "Sh 2-82". galaxymap.org. Retrieved 2025-11-16.
  5. ↑ Forbes, D. (March 1989). "Photometry and spectroscopy of stars in northern H II regions". Astronomy and Astrophysics Supplement Series. 77. ISSN   0365-0138. Archived from the original on 2025-02-23.
  6. ↑ "Simbad - Object view". simbad.cds.unistra.fr. Retrieved 2025-11-16.
  7. ↑ "SH2-82 (Little Coccoon Nebula)". www.sharplesscatalog.com. Retrieved 2025-11-16.
  8. ↑ Brecher, Ron (2022-10-24). "Sh2-82, The Little Cocoon Nebula". Astrodoc: Astrophotography by Ron Brecher. Retrieved 2025-11-16.
  9. 1 2 "Hanson Astrophotography-Sharpless 82". Hanson Astrophotography. Retrieved 2025-11-16.
  10. ↑ "LDN 727". simbad.cds.unistra.fr. Retrieved 2025-11-16.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.