{{short description|Globular cluster in the constellation Coma Berenices}} {{Infobox globular cluster | name = [[New General Catalogue|NGC]] 5053 | image = File:NGC5053 - SDSS DR14 (panorama).jpg | caption = | credit = | epoch = J2000 | class = XI | constellation = [[Coma Berenices]] | ra = {{RA|13|16|27.09}}<ref name=aj140_6_1830/> | dec = {{DEC|+17|42|00.9}}<ref name=aj140_6_1830/> | dist_ly = {{Convert|17.4|kpc|kly|lk=on|abbr=on}}<ref name=boberg2015/> | appmag_v = 9.96<ref name=Dalessandro2012/> | size_v = 10.5' | mass_msol = | mass_kg = | radius_arcminsec = | radius_ly = | radius_pc = | radius_tidal_pc = {{Convert|89.13|pc|ly|abbr=on}}<ref name=boberg2015/> | v_hb = | metal_fe = −2.30<ref name=Dalessandro2012/> | metal_z = | age = {{Val|12.3|0.7|ul=Gyr}}<ref name=arellano2010/> | notes = | names = [[Collinder catalogue|Cr]] 267, C 1313+179, GCl 23 }} '''NGC 5053''' is a [[globular cluster]] in the northern [[constellation]] of [[Coma Berenices]]. It was discovered by German-British astronomer [[William Herschel]] on March 14, 1784 and cataloged as VI-7. In his abbreviated notation, he described it as "an extremely faint cluster of extremely small stars with resolvable nebula 8 or 10′ diameter, verified by a power of 240, beyond doubt".<ref name=Herschel1786/> Danish-Irish astronomer [[John Louis Emil Dreyer]] reported in 1888 that the cluster appeared, "very faint, pretty large, irregular round shape, growing very gradually brighter at the middle".<ref name=dreyer1971/>

This is a metal-poor cluster, meaning the stars have a low abundance of elements other than hydrogen and helium—what astronomers term [[metallicity]]. As recently as 1995, it was considered the most metal-poor globular cluster in the [[Milky Way]].<ref name=sarajedina1995/> The chemical abundances of the stars in NGC 5053 are more similar to those in the dwarf galaxy [[Sagittarius Dwarf Spheroidal Galaxy]] than to the [[Milky Way halo]]. Along with the [[kinematics]] of the globular cluster, this suggests that NGC 5053 may have been stripped from the dwarf galaxy.<ref name=Sbordone2015/>

There are ten known [[RR Lyrae variable]] stars in this cluster with masses ranging from 68% to 78% of the [[solar mass]]. Nine of these variables were reported by German astronomer [[Walter Baade]] in 1928, and the tenth by American astronomer [[Helen Sawyer Hogg|Helen Sawyer]] in 1946.<ref name=nemec2004/> The cluster hosts 27 known [[blue straggler]]s,<ref name=arellano2010/> of which five are short period [[SX Phoenicis variable]] stars.<ref name=nemec2004/>

NGC 5053 is a relatively low mass cluster with a low core concentration factor of 1.32. It sports a stream of [[tidal debris]] to the west with a projected length of 1.7&nbsp;kpc. This stream may have been created through [[Tidal shock|shock]]-induced processes.<ref name=Lauchner2006/> The cluster is located less than 1° from [[Messier 53]] and the two have nearly the same [[distance modulus]], which corresponds to a spatial separation of around 2&nbsp;kpc. There is a tidal bridge joining M53 to NGC 5053, suggesting the pair may have interacted in the past.<ref name=boberg2015/> The cluster is following an orbit through the [[Milky Way]] that has a [[perigalacticon]] distance of 9&nbsp;kpc and an [[orbital eccentricity]] of 0.84.<ref name=Lauchner2006/> At present, it is 18.4&nbsp;kpc from the [[Galactic Center]], with a [[radial velocity]] of {{Val|42.0|1.4|u=km/s}}.<ref name=boberg2015/>

== References == {{Reflist|refs=

<ref name=aj140_6_1830>{{citation | display-authors=1 | last1=Goldsbury | first1=Ryan | last2=Richer | first2=Harvey B. | last3=Anderson | first3=Jay | last4=Dotter | first4=Aaron | last5=Sarajedini | first5=Ata | last6=Woodley | first6=Kristin | title=The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters | journal=The Astronomical Journal | volume=140 | issue=6 | pages=1830–1837 |date=December 2010 | doi=10.1088/0004-6256/140/6/1830 | bibcode=2010AJ....140.1830G | arxiv=1008.2755 | s2cid=119183070 | postscript=. }}</ref>

<ref name=Dalessandro2012>{{citation | display-authors=1 | last1=Dalessandro | first1=Emanuele | last2=Schiavon | first2=Ricardo P. | last3=Rood | first3=Robert T. | last4=Ferraro | first4=Francesco R. | last5=Sohn | first5=Sangmo T. | last6=Lanzoni | first6=Barbara | last7=O'Connell | first7=Robert W. | title=Ultraviolet Properties of Galactic Globular Clusters with Galex. II. Integrated Colors | journal=The Astronomical Journal | volume=144 | issue=5 | id=126 | pages=13 | date=November 2012 | doi=10.1088/0004-6256/144/5/126 | bibcode=2012AJ....144..126D | arxiv=1208.5698 | s2cid=56419886 | postscript=. }}</ref>

<ref name=Sbordone2015>{{citation | display-authors=1 | last1=Sbordone | first1=L. | last2=Monaco | first2=L. | last3=Moni Bidin | first3=C. | last4=Bonifacio | first4=P. | last5=Villanova | first5=S. | last6=Bellazzini | first6=M. | last7=Ibata | first7=R. | last8=Chiba | first8=M. | last9=Geisler | first9=D. | last10=Caffau | first10=E. | last11=Duffau | first11=S. | title=Chemical abundances of giant stars in NGC 5053 and NGC 5634, two globular clusters associated with the Sagittarius dwarf spheroidal galaxy? | journal=Astronomy & Astrophysics | volume=579 | id=A104 | pages=12 | date=July 2015 | doi=10.1051/0004-6361/201425509 | bibcode=2015A&A...579A.104S | arxiv=1505.01487 | s2cid=55408091 | postscript=. }}</ref>

<ref name=Lauchner2006>{{citation | display-authors=1 | last1=Lauchner | first1=Adam | last2=Powell | first2=W. Lee Jr. | last3=Wilhelm | first3=Ronald | title=Discovery of a Tidal Stream Extending from NGC 5053 | journal=The Astrophysical Journal | volume=651 | issue=1 | pages=L33–L36 | date=November 2006 | doi=10.1086/509254 | bibcode=2006ApJ...651L..33L | postscript=. | doi-access=free }}</ref>

<ref name=boberg2015>{{citation | display-authors=1 | last1=Boberg | first1=Owen M. | last2=Friel | first2=Eileen D. | last3=Vesperini | first3=Enrico | title=Chemical Abundances in NGC 5053: A Very Metal-poor and Dynamically Complex Globular Cluster | journal=The Astrophysical Journal | volume=804 | issue=2 | id=109 | pages=12 | date=May 2015 | doi=10.1088/0004-637X/804/2/109 | bibcode=2015ApJ...804..109B | arxiv=1504.01791 | s2cid=117834526 | postscript=. }}</ref>

<ref name=nemec2004>{{citation | last1=Nemec | first1=James M. | title=Physical Characteristics of the RR Lyrae Stars in the Very Metal Poor Globular Cluster NGC 5053 | journal=The Astronomical Journal | volume=127 | issue=4 | pages=2185–2209 | date=April 2004 | doi=10.1086/382903 | bibcode=2004AJ....127.2185N | postscript=. | doi-access=free }}</ref>

<ref name=arellano2010>{{citation | display-authors=1 | last1=Arellano Ferro | first1=A. | last2=Giridhar | first2=Sunetra | last3=Bramich | first3=D. M. | title=CCD time-series photometry of the globular cluster NGC 5053: RR Lyrae, Blue Stragglers and SX Phoenicis stars revisited | journal=Monthly Notices of the Royal Astronomical Society | volume=402 | issue=1 | pages=226–244 | date=February 2010 | doi=10.1111/j.1365-2966.2009.15931.x | doi-access=free | bibcode=2010MNRAS.402..226A | arxiv=0910.2068 | s2cid=119301509 | postscript=. }}</ref>

<ref name=sarajedina1995>{{citation | last1=Sarajedini | first1=Ata | last2=Milone | first2=Alejandra A. E. | title=BVI CCD photometry of NGC 5053: The most metal-poor galactic globular cluster | journal=The Astronomical Journal | volume=109 | issue=1669 | pages=269–279 | date=January 1995 | doi=10.1086/117271 | bibcode=1995AJ....109..269S | postscript=. | doi-access=free }}</ref>

<ref name=dreyer1971>{{citation | first1=John L. E. | last1=Dreyer | page=141 | year=1971 | title=New General Catalogue of Nebulae and Clusters of Stars | journal=Memoirs of the Royal Astronomical Society | url=https://archive.org/details/NewGeneralCatalogueOfNebulaeAndClustersOfStarsIndexCatalogue | access-date=2016-08-08 | postscript=. }}</ref>

<ref name=Herschel1786>{{citation | title=Catalogue of One Thousand New Nebulae and Clusters of Stars | last1=Herschel | first1=William | journal=Philosophical Transactions of the Royal Society of London | volume=76 | pages=457–499 | year=1786 | bibcode=1786RSPT...76..457H | postscript=See p. 495. | doi=10.1098/rstl.1786.0027| url=https://zenodo.org/record/1432282| doi-access=free}}</ref>

}}

== External links== {{commonscat}} *[https://twitter.com/xipteras/status/1201191848552882178 Wide angle view with M53] Panagiotis Xipteras

{{Ngc55}} {{Coma Berenices}}

{{DEFAULTSORT:NGC 5053}} [[Category:Coma Berenices]] [[Category:Globular clusters]] [[Category:NGC objects|5053]]