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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Anticenter shell</span></span>
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</style><table class="infobox"><caption class="infobox-title">Anticenter Shell</caption><tbody><tr><th colspan="2" class="infobox-above" style="background: #eeddff;"><a href="Superbubble" title="Superbubble">Superbubble</a></th></tr><tr><th colspan="2" class="infobox-header" style="background: #eeddff;">Observation data: <a href="B1950.0" class="mw-redirect" title="B1950.0">B1950.0</a> <a href="Epoch_(astronomy)" title="Epoch (astronomy)">epoch</a></th></tr><tr><th scope="row" class="infobox-label" style="background: inherit;"><a href="Right_ascension" title="Right ascension">Right ascension</a></th><td class="infobox-data"><span class="nowrap">06<sup>h</sup> 27<sup>m</sup> </span></td></tr><tr><th scope="row" class="infobox-label" style="background: inherit;"><a href="Declination" title="Declination">Declination</a></th><td class="infobox-data">+15°</td></tr><tr><th scope="row" class="infobox-label" style="background: inherit;">Distance</th><td class="infobox-data">55 k <a href="Light-year" title="Light-year">ly</a> (17 k <a href="Parsec" title="Parsec">pc</a>)</td></tr><tr></tr></tbody></table>
<p>The <b>anticenter shell</b> or <b>anticenter superbubble</b> is a region near the <a href="Galactic_anticenter" title="Galactic anticenter">anticenter</a> of the <a href="Milky_Way_Galaxy" class="mw-redirect" title="Milky Way Galaxy">Milky Way Galaxy</a> that emits <a href="21_cm_radiation" class="mw-redirect" title="21 cm radiation">21 cm radiation</a>. It is located at <span class="nowrap">06<sup>h</sup> 27<sup>m</sup> </span> +15°, or l = 197°, b = +2° in <a href="Galactic_coordinates" class="mw-redirect" title="Galactic coordinates">galactic coordinates</a>,<sup id="cite_ref-Simonson_1-0" class="reference"><a href="#cite_note-Simonson-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> near the border of the constellations <a href="Gemini_(constellation)" title="Gemini (constellation)">Gemini</a> and <a href="Orion_(constellation)" title="Orion (constellation)">Orion</a>. It is a <a href="Supershell" class="mw-redirect" title="Supershell">supershell</a> (a very large <a href="Superbubble" title="Superbubble">superbubble</a>) within our galaxy that is spherical in shape and features jets of gas.
</p><p>Discovered in 1970, this <a href="Galaxy" title="Galaxy">galactic</a> object has subsequently been variously classified by researchers as a spiral arm of the Milky Way in 1972, a nearby <a href="Tidal_stripping" title="Tidal stripping">tidally-stripped</a> <a href="Dwarf_galaxy" title="Dwarf galaxy">dwarf galaxy</a> in 1975, and a <a href="High-velocity_cloud" title="High-velocity cloud">high-velocity cloud</a> in 1979.<sup id="cite_ref-Tamanaha_2-0" class="reference"><a href="#cite_note-Tamanaha-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup>
</p><p>The name <b>Snickers</b> for the anticenter shell arose from the description in 1975 by Christian Simonson, a <a href="University_of_Maryland%2C_College_Park" title="University of Maryland, College Park">University of Maryland</a> <a href="Astronomer" title="Astronomer">astronomer</a> who believed it to be a small "peanut" of a <a href="Galaxy" title="Galaxy">galaxy</a> just outside the Milky Way.<sup id="cite_ref-Simonson_1-1" class="reference"><a href="#cite_note-Simonson-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>
Simonson's colleagues coined the name <i>Snickers</i> (in reference to the American chocolate bars <i><a href="Milky_Way_bar" class="mw-redirect" title="Milky Way bar">Milky Way</a></i> and <i><a href="Snickers" title="Snickers">Snickers</a></i>) due to its proximity to the Milky Way. Less popularly, the anticenter superbubble is also referred to as <b>0627-15</b> from its equatorial coordinates.<sup id="cite_ref-Time_4-0" class="reference"><a href="#cite_note-Time-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup>
</p><p>The anticenter shell is approximately 55,000 light years (17 <a href="Kiloparsec" class="mw-redirect" title="Kiloparsec">kpc</a>) from the Sun.<sup id="cite_ref-Simonson_1-2" class="reference"><a href="#cite_note-Simonson-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Its dimensions are difficult to determine by <a href="Radio_wave" title="Radio wave">radio observation</a> due to its location near the <a href="Zone_of_Avoidance" title="Zone of Avoidance">Zone of Avoidance</a>, the regions of the sky obscured by <a href="Interstellar_dust" class="mw-redirect" title="Interstellar dust">interstellar dust</a> along the galactic equator.
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<div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div>
<ul><li><a href="List_of_stellar_streams" title="List of stellar streams">List of stellar streams</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
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<li id="cite_note-Simonson-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Simonson_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Simonson_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Simonson_1-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">
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</style><cite id="CITEREFSimonson1975" class="citation journal cs1">Simonson, S. Christian, III. (1975). "A New Milky Way Satellite Found in 21-Centimeter Line Observations". <i><a href="Astrophysical_Journal_Letters" class="mw-redirect" title="Astrophysical Journal Letters">Astrophysical Journal Letters</a></i>. <b>201</b>: <span class="nowrap">L103 –</span> <span class="nowrap">L108</span>. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1975ApJ...201L.103S">1975ApJ...201L.103S</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F181952">10.1086/181952</a>.</cite><span class="cs1-maint citation-comment"><code class="cs1-code">{{cite journal}}</code>: CS1 maint: multiple names: authors list (link)</span></span>
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<li id="cite_note-Tamanaha-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-Tamanaha_2-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFTamanaha1997" class="citation journal cs1">Tamanaha, Christopher M. (1997). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F312975">"The Anticenter Shell and the Anticenter Chain"</a>. <i><a href="Astrophysical_Journal_Supplement_Series" class="mw-redirect" title="Astrophysical Journal Supplement Series">Astrophysical Journal Supplement Series</a></i>. <b>109</b> (1): <span class="nowrap">139–</span>175. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1997ApJS..109..139T">1997ApJS..109..139T</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F312975">10.1086/312975</a></span>.</cite></span>
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<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20071017213943/http://astroprofspage.com/archives/117">"Snickers"</a>. <i>Astroprof's Page</i>. 2006-02-28. Archived from <a rel="nofollow" class="external text" href="http://astroprofspage.com/archives/117">the original</a> on 2007-10-17<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-02-01</span></span>.</cite></span>
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<li id="cite_note-Time-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-Time_4-0">^</a></b></span> <span class="reference-text"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20080209030517/http://www.time.com/time/magazine/article/0%2C9171%2C913757%2C00.html">"Peanuts in the Sky"</a>. <i><a href="Time_(magazine)" title="Time (magazine)">Time</a></i>. 1975-11-24. Archived from <a rel="nofollow" class="external text" href="http://www.time.com/time/magazine/article/0,9171,913757,00.html">the original</a> on 9 February 2008<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-02-01</span></span>.</cite></span>
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