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.
The loop extends over about 600 arcminutes as seen from Earth, covering much of Orion. It is well seen in long-exposure photographs, although observers under very dark skies may be able to see it with the naked eye.
Recent estimates place it at a distance of either 159 pc (518 light years)[1] or 440 pc (1434 ly)[2] giving it dimensions of either about 100 or 300 ly across respectively. It is thought to have originated in a supernova explosion about 2 million years ago, which may have also created several known runaway stars, including AE Aurigae, Mu Columbae and 53 Arietis, which are believed to have been part of a multiple star system in which one component exploded as a supernova.[3]
Although this faint nebula was certainly observed by earlier astronomers, it is named after the pioneering astrophotographerE. E. Barnard who photographed it and published a description in 1894.[4]
Above photo of Barnard's Loop nebula in inverted black and white of the red channel
Long exposure of Orion with red clouds of ionized hydrogen (H-alpha). The big bow on the left is Barnard's Loop.
Barnard's Loop seen against the major stars and nebula of Orion
Referencesedit
^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. S2CID 13916583.
^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. S2CID 5019523.
^"The Internet Encyclopedia of Science: Barnard's Loop (Sh 2-276)". David Darling. from the original on 12 March 2008. Retrieved 2008-04-22.
^Barnard, E. E. (1894). "The great photographic nebula of Orion, encircling the belt and theta nebula". Popular Astronomy. 2: 151–154. Bibcode:1894PA......2..151B. doi:10.1086/102137.
Reynolds, R. J.; Ogden, P. M. (1979), "Optical evidence for a very large, expanding shell associated with the I Orion OB association, Barnard's loop, and the high galactic latitude H-alpha filaments in Eridanus", Astrophysical Journal, 229: 942–953, Bibcode:1979ApJ...229..942R, doi:10.1086/157028
External linksedit
Wikimedia Commons has media related to Barnard's Loop.
Photograph identifying several nebulae in Orion
Encyclopaedia of Astrobiology, Astronomy, and Spaceflight entry
barnard, loop, catalogue, designation, emission, nebula, constellation, orion, part, orion, molecular, cloud, complex, which, also, contains, dark, horsehead, bright, orion, nebulae, loop, takes, form, large, centered, approximately, orion, nebula, stars, with. 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 Barnard s LoopEmission nebulaH II regionBarnard s Loop can be seen on this image as a diffuse red semicircle Observation data J2000 epochRight ascension05h 27 5mDeclination 03 58 Distanceeither 518 or 1434 lyApparent magnitude V 5Apparent dimensions V 10 ConstellationOrionPhysical characteristicsRadiuseither 50 or 150 lyDesignationsSh 2 276See also Lists of nebulaeThe loop extends over about 600 arcminutes as seen from Earth covering much of Orion It is well seen in long exposure photographs although observers under very dark skies may be able to see it with the naked eye Recent estimates place it at a distance of either 159 pc 518 light years 1 or 440 pc 1434 ly 2 giving it dimensions of either about 100 or 300 ly across respectively It is thought to have originated in a supernova explosion about 2 million years ago which may have also created several known runaway stars including AE Aurigae Mu Columbae and 53 Arietis which are believed to have been part of a multiple star system in which one component exploded as a supernova 3 Although this faint nebula was certainly observed by earlier astronomers it is named after the pioneering astrophotographer E E Barnard who photographed it and published a description in 1894 4 Above photo of Barnard s Loop nebula in inverted black and white of the red channel Long exposure of Orion with red clouds of ionized hydrogen H alpha The big bow on the left is Barnard s Loop Barnard s Loop seen against the major stars and nebula of OrionReferences edit 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 amp A 430 523W doi 10 1051 0004 6361 20035943 S2CID 13916583 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 S2CID 5019523 The Internet Encyclopedia of Science Barnard s Loop Sh 2 276 David Darling Archived from the original on 12 March 2008 Retrieved 2008 04 22 Barnard E E 1894 The great photographic nebula of Orion encircling the belt and theta nebula Popular Astronomy 2 151 154 Bibcode 1894PA 2 151B doi 10 1086 102137 Gaylard M J 1984 Detection of the H 142 alpha line from the Barnard Loop Monthly Notices of the Royal Astronomical Society 211 149 153 doi 10 1093 mnras 211 1 149 Reynolds R J Ogden P M 1979 Optical evidence for a very large expanding shell associated with the I Orion OB association Barnard s loop and the high galactic latitude H alpha filaments in Eridanus Astrophysical Journal 229 942 953 Bibcode 1979ApJ 229 942R doi 10 1086 157028External links edit nbsp Wikimedia Commons has media related to Barnard s Loop Photograph identifying several nebulae in Orion Encyclopaedia of Astrobiology Astronomy and Spaceflight entry The Scale of the Universe Astronomy Picture of the Day 12 March 2012 Retrieved from https en wikipedia org w index php title Barnard 27s Loop amp oldid 1183985682, wikipedia, wiki, book, books, library,
