Editing Ursa Minor (section)

=== Deep-sky objects ===
[[File:NGC 6217 hs-2009-25-bc-full.jpg|thumb|right|NGC 6217]]
Ursa Minor is rather devoid of deep-sky objects. The [[Ursa Minor Dwarf]], a [[dwarf spheroidal galaxy]], was discovered by [[Albert George Wilson]] of the [[Lowell Observatory]] in the [[National Geographic Society – Palomar Observatory Sky Survey|Palomar Sky Survey]] in 1955.<ref>{{cite book|last=Bergh|first=Sidney |title=The Galaxies of the Local Group|publisher=Cambridge University Press|location=Cambridge, UK|date=2000|page=257|isbn=978-1-139-42965-8|url=https://books.google.com/books?id=H0JMeoqFqEcC&q=variable+stars+ursa+minor&pg=PA257}}</ref> Its centre is around {{val|225,000}} light-years distant from Earth.<ref>{{cite journal|author=Grebel, Eva K.|author2=Gallagher, John S., III|author3=Harbeck, Daniel|title=The Progenitors of Dwarf Spheroidal Galaxies|journal=The Astronomical Journal|date=2003|volume=125|issue=4|pages=1926–39|doi=10.1086/368363 | bibcode=2003AJ....125.1926G|arxiv = astro-ph/0301025 |s2cid=18496644}}</ref> In 1999, Kenneth Mighell and Christopher Burke used the [[Hubble Space Telescope]] to confirm that the galaxy had had a single burst of [[star formation]] that took place around 14&nbsp;billion years ago and lasted around 2&nbsp;billion years,<ref name="Bergh2000">{{Cite journal | last1 = van den Bergh | first1 = Sidney | author-link1 = Sidney van den Bergh | title = Updated Information on the Local Group  | date = April 2000 | journal = The Publications of the Astronomical Society of the Pacific | volume = 112 | issue = #770 | bibcode = 2000PASP..112..529V | pages = 529–36 | doi = 10.1086/316548 |arxiv = astro-ph/0001040 | s2cid = 1805423 }}</ref> and that the galaxy was probably as old as the Milky Way itself.<ref>{{cite journal|author=Mighell, Kenneth J.|author2=Burke, Christopher J.|date=1999|title=WFPC2 Observations of the Ursa Minor Dwarf Spheroidal Galaxy|journal=The Astronomical Journal|volume=118|issue=366|pages=366–380|doi=10.1086/300923|arxiv = astro-ph/9903065 |bibcode = 1999AJ....118..366M |s2cid=119085245}}</ref>

[[NGC 3172]] (also known as Polarissima Borealis) is a faint, magnitude-14.9 [[galaxy]] that happens to be the closest [[NGC object]] to the [[north celestial pole]].<ref name="SIMBAD NGC3172">{{Cite web|title=NGC 3172|url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%40331138&Name=NGC++3172&submit=display+all+measurements#lab_meas%20SIMBAD:%20NGC%203054%20--%20Galaxy|website=sim-id|access-date=2020-05-29}}</ref> It was discovered by [[John Herschel]] in 1831.<ref>{{Cite web|title=New General Catalog Objects: NGC 3150 - 3199|url=https://cseligman.com/text/atlas/ngc31a.htm#3172|website=cseligman.com|access-date=2020-05-30}}</ref>

[[NGC 6217]] is a [[barred spiral galaxy]] located some 67 million light-years away,<ref name="Gusev2012">{{Cite journal  | last1   = Gusev | first1  = A. S. | last2   = Pilyugin | first2  = L. S. | last3   = Sakhibov | first3  = F. | last4   = Dodonov | first4  = S. N. | last5   = Ezhkova | first5  = O. V. | last6   = Khramtsova | first6  = M. S. | last7   = Garzónhuhed | first7  = F. | title   = Oxygen and Nitrogen Abundances of H II regions in Six Spiral Galaxies | journal = [[Monthly Notices of the Royal Astronomical Society]] | volume  = 424 | issue   = #3 | pages   = 1930–40 |date=2012 | arxiv   = 1205.3910 | doi     = 10.1111/j.1365-2966.2012.21322.x | doi-access = free | bibcode = 2012MNRAS.424.1930G| s2cid = 118437910 }}</ref> which can be located with a {{Convert|4|in|cm|abbr=on|order=flip}} or larger [[telescope]] as an 11th-magnitude object about 2.5° east-northeast of Zeta Ursae Minoris.<ref name="OMeara2007">{{Cite book | first1  = Stephen James | last1= O'Meara | title= Steve O'Meara's Herschel 400 Observing Guide | publisher = Cambridge University Press |location=Cambridge, UK| page= 227 | date = 2007 | isbn= 978-0-521-85893-9 | url = https://books.google.com/books?id=Nyh9fAC_tpIC&pg=PA227}}</ref> It has been characterized as a [[starburst galaxy]], which means it is undergoing a high rate of star formation compared with a typical galaxy.<ref>{{cite journal|last= Calzetti|first=Daniela|author-link= Daniela Calzetti |date=1997|title=Reddening and Star Formation in Starburst Galaxies|journal=Astronomical Journal|volume=113|pages=162–84|doi=10.1086/118242 | bibcode=1997AJ....113..162C|arxiv = astro-ph/9610184 |s2cid=16526015}}</ref>

[[NGC 6251]] is an active supergiant elliptical [[radio galaxy]] more than 340 million light-years away from Earth. It has a Seyfert 2 [[active galactic nucleus]], and is one of the most extreme examples of a [[Seyfert galaxy]]. This galaxy may be associated with gamma-ray source 3EG J1621+8203, which has high-energy gamma-ray emission.<ref name=SIMBADngc6251>{{cite web |url =http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=QSO+B1637%2B826 |title = NGC 6251 – Seyfert 2 Galaxy  |work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg |access-date = 21 July 2015}}</ref><!-- cites previous 3 sentences --> It is also noted for its one-sided [[Astrophysical jet|radio jet]]—one of the brightest known—discovered in 1977.<ref>{{cite journal|author1=Perley, R. A. |author2=Bridle, A. H. |author3=Willis, A. G. |date=1984|title=High-resolution VLA Observations of the Radio Jet in NGC 6251|journal=Astrophysical Journal Supplement Series|volume=54|pages=291–334|doi=10.1086/190931 | bibcode=1984ApJS...54..291P}}</ref>