APOD: LDN 1622: Dark Nebula in Orion (2020 Feb 21)

[APOD Robot]

LDN 1622: Dark Nebula in Orion

Explanation: The silhouette of an intriguing dark nebula inhabits this cosmic scene. Lynds' Dark Nebula (LDN) 1622 appears against a faint background of glowing hydrogen gas only visible in long telescopic exposures of the region. In contrast, the brighter reflection nebula vdB 62 is more easily seen, just above and right of center. LDN 1622 lies near the plane of our Milky Way Galaxy, close on the sky to Barnard's Loop, a large cloud surrounding the rich complex of emission nebulae found in the Belt and Sword of Orion. With swept-back outlines, the obscuring dust of LDN 1622 is thought to lie at a similar distance, perhaps 1,500 light-years away. At that distance, this 1 degree wide field of view would span about 30 light-years. Young stars do lie hidden within the dark expanse and have been revealed in Spitzer Space telescope infrared images. Still, the foreboding visual appearance of LDN 1622 inspires its popular name, the Boogeyman Nebula.

<< Previous APOD

This Day in APOD

Next APOD >>

[Donald Pelletier]

All the sources consulted mention a distance of 400 to 500 light years, as well as previous APOD publications. We would like to know where this new distance comes from.

[Boomer12k]

It is ironic that such a dark place... gives birth to sources of light...

:---[===] *

[orin stepanek]

Yup, dark until the light turns on!
Kind of Looks like the nebula has eyes!

[neufer]

All the sources consulted mention a distance of 400 to 500 light years, as well as previous APOD publications. We would like to know where this new distance comes from.

• All the sources prior to 2011 probably would:

https://en.wikipedia.org/wiki/Barnard%27s_Loop

<<Barnard's Loop (catalogue designation Sh 2-276) is an emission nebula in the constellation of Orion. It is part of the Orion Molecular Cloud Complex which also contains the dark Horsehead and bright Orion nebulae. The loop takes the form of a large arc centered approximately on the Orion Nebula. The stars within the Orion Nebula are believed to be responsible for ionizing the loop.

Recent estimates place [Barnard's Loop] at a distance of either:

• 159 pc (518 light years)
  
  Wilson, B.A.; Dame, T.M.; Masheder, M.R.W.; Thaddeus, P. (2005). "A uniform CO survey of the molecular clouds in Orion and Monoceros". Astronomy and Astrophysics. 430 (2): 523–539. arXiv:astro-ph/0411089v1. Bibcode:2005A&A...430..523W. doi:10.1051/0004-6361:20035943.
  
  or 440 pc (1434 ly)
  
  O'Dell, C.R.; Ferland, G.J.; Porter, R.L.; van Hoof, P.A.M. (2011). "Physical Conditions in Barnard's Loop, Components of the Orion-eridanus Bubble, and Implications for the Warm Ionized Medium Component of the Interstellar Medium". The Astrophysical Journal. 733 (1): 9. arXiv:1103.2789. Bibcode:2011ApJ...733....9O. doi:10.1088/0004-637X/733/1/9.

[TheZuke!]

It looks like a beaver doing the back stroke.