[{"@context":"http:\/\/schema.org\/","@type":"BlogPosting","@id":"https:\/\/wiki.edu.vn\/en\/wiki41\/sh2-308-wikipedia\/#BlogPosting","mainEntityOfPage":"https:\/\/wiki.edu.vn\/en\/wiki41\/sh2-308-wikipedia\/","headline":"Sh2-308 – Wikipedia","name":"Sh2-308 – Wikipedia","description":"before-content-x4 From Wikipedia, the free encyclopedia after-content-x4 Emission nebula Sh2-308, also designated as Sharpless 308, RCW 11, or LBN 1052,[1]","datePublished":"2017-03-11","dateModified":"2017-03-11","author":{"@type":"Person","@id":"https:\/\/wiki.edu.vn\/en\/wiki41\/author\/lordneo\/#Person","name":"lordneo","url":"https:\/\/wiki.edu.vn\/en\/wiki41\/author\/lordneo\/","image":{"@type":"ImageObject","@id":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","height":96,"width":96}},"publisher":{"@type":"Organization","name":"Enzyklop\u00e4die","logo":{"@type":"ImageObject","@id":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","url":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","width":600,"height":60}},"image":{"@type":"ImageObject","@id":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/d\/df\/SH2-308.jpg\/120px-SH2-308.jpg","url":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/d\/df\/SH2-308.jpg\/120px-SH2-308.jpg","height":"120","width":"120"},"url":"https:\/\/wiki.edu.vn\/en\/wiki41\/sh2-308-wikipedia\/","about":["Wiki"],"wordCount":2790,"articleBody":"     (adsbygoogle = window.adsbygoogle || []).push({});before-content-x4From Wikipedia, the free encyclopedia       (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4Emission nebulaSh2-308, also designated as Sharpless 308, RCW 11, or LBN 1052,[1] and commonly known as the Dolphin-Head Nebula, is an H II region located near the center of the constellation Canis Major, composed of ionised hydrogen.[2] It is about 8 degrees south of Sirius, the brightest star in the night sky. The nebula is bubble-like and surrounds a Wolf\u2013Rayet star named EZ Canis Majoris. This star is in the brief, pre-supernova phase of its stellar evolution. The nebula is about 4,530 light-years (1,389 parsecs) away from Earth,[3] but some sources indicate that both the star and the nebula are up to 5,870\u00a0ly (1,800\u00a0pc) away.[4][5] Yet others indicate the nebula is as close as 1,875\u00a0ly (575\u00a0pc) from Earth.[6]       (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4Table of ContentsCentral star[edit]Formation[edit]Observation[edit]Gallery[edit]References[edit]External links[edit]Central star[edit]Sh2-308 surrounds the Wolf\u2013Rayet star EZ Canis Majoris, also designated EZ CMa or WR 6. Its apparent magnitude varies from 6.71 to 6.95. Its spectral type indicates that the star is very hot and luminous. The spectrum shows that it is devoid of hydrogen at the surface.[7] EZ Canis Majoris is expected eventually to explode in a supernova, therefore subsuming the nebula.[8]Formation[edit]The nebula was formed about 70,000 years ago by the star EZ Canis Majoris throwing off its outer hydrogen layers, revealing inner layers of heavier elements.[2] Fast stellar winds, blowing at 1,700\u00a0km\/s (3.8\u00a0million\u00a0mph) from this star, create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of the star’s evolution. The hydrogen composing the nebula is ionised by intense ultraviolet radiation.[9] The nebula is approximately 60 light-years across at its widest point.[10]       (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4Observation[edit]The most favorable period for observing the nebula in the night sky is between the months of December and April. Its southern declination makes it easier to observe from the Southern Hemisphere, though it is easily visible from most of the Northern Hemisphere as well. It appears as a faint cloud in photographs taken with high-power amateur instruments, with the help of special filters.Gallery[edit]Dolphin Head Nebula \u2013 SH2-308. Processed by Jim DeLillo via TelescopeLive One-Click ImagingReferences[edit]^ “Sh 2-308”. SIMBAD. Centre de donn\u00e9es astronomiques de Strasbourg. Retrieved 2017-04-30.^ a b “Inflating Sh2-308”. www.spacetelescope.org. Retrieved 2017-05-22.^ van Leeuwen, F. (2007-11-01). “Validation of the new Hipparcos reduction”. Astronomy and Astrophysics. 474 (2): 653\u2013664. arXiv:0708.1752. Bibcode:2007A&A…474..653V. doi:10.1051\/0004-6361:20078357. ISSN\u00a00004-6361. S2CID\u00a018759600.^ “APOD: 2009 April 23 – Sharpless 308”. apod.nasa.gov. Retrieved 2017-05-02.^ Morris, P W; Crowther, P A; Houck, J R (2004-06-01). “Spitzer-IRS Sectroscopy of the Prototype Wolf\u2013Rayet star EZ CMa (HD 50896)”. arXiv:astro-ph\/0406074.^ Burningham, Ben; Naylor, Tim; Jeffries, R. D.; Devey, C. R. (2003-12-01). “On the nature of Collinder 121: insights from the low-mass pre-main sequence”. Monthly Notices of the Royal Astronomical Society. 346 (4): 1143\u20131150. arXiv:astro-ph\/0308488. Bibcode:2003MNRAS.346.1143B. doi:10.1111\/j.1365-2966.2003.07160.x. ISSN\u00a00035-8711. S2CID\u00a016366019.^ Hamann, W.-R.; Gr\u00e4fener, G.; Liermann, A. (2006). “The Galactic WN stars”. Astronomy and Astrophysics. 457 (3): 1015. arXiv:astro-ph\/0608078. Bibcode:2006A&A…457.1015H. doi:10.1051\/0004-6361:20065052. S2CID\u00a018714731.^ “Hubble Image of the Week – EZ Canis Majoris, Sh2-308”. SciTech Daily. 2017-04-17. Retrieved 2017-05-26.^ Toal\u00e1, J. A.; Guerrero, M. A.; Ramos-Larios, G.; Guzm\u00e1n, V. (2015). “WISE morphological study of Wolf-Rayet nebulae”. Astronomy & Astrophysics. 578: A66. arXiv:1503.06878. Bibcode:2015A&A…578A..66T. doi:10.1051\/0004-6361\/201525706. ISSN\u00a00004-6361. S2CID\u00a055776698.^ Hille, Karl (2017-04-21). “Hubble’s Cosmic Bubbles”. NASA. Retrieved 2017-04-30.External links[edit]Wikimedia Commons has media related to Sh2-308.     (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4"},{"@context":"http:\/\/schema.org\/","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"https:\/\/wiki.edu.vn\/en\/wiki41\/#breadcrumbitem","name":"Enzyklop\u00e4die"}},{"@type":"ListItem","position":2,"item":{"@id":"https:\/\/wiki.edu.vn\/en\/wiki41\/sh2-308-wikipedia\/#breadcrumbitem","name":"Sh2-308 – Wikipedia"}}]}]