{{Short description|Galaxy in the constellation Boötes}} {{Infobox Galaxy | name = [[Uppsala General Catalogue|UGC]] 9128 | image = UGC 9128.jpg | caption = UGC 9128 imaged by the [[Hubble Space Telescope]] | epoch = J2000 | ra = {{RA|14|15|56.70}}<ref name=Cotton>{{cite journal|bibcode=1999ApJS..125..409C|doi=10.1086/313286|title=Arcsecond Positions of UGC Galaxies|year=1999|last1=Cotton|first1=W. D.|last2=Condon|first2=J. J.|last3=Arbizzani|first3=E.|journal=The Astrophysical Journal Supplement Series|volume=125|issue=2|pages=409–412|s2cid=122517686 |doi-access=free}}</ref> | dec = {{DEC|23|03|16.2}}<ref name=Cotton/> | dist_ly = 6.8–7.8 [[light-year|Mly]] (2.1–2.4 [[parsec|Mpc]])<ref name="telescope1" /><ref name="starburst1"/> | mass = {{val|1.3|0.2|e=7}} <ref name="starburst1">{{cite web |title=Dynamics of starbursting dwarf galaxies |url=https://www.aanda.org/articles/aa/pdf/2014/06/aa22657-13.pdf |access-date=8 August 2021}}</ref> | size = 3300 [[light-year|ly]]<ref name="slate1" /> | type = dIrr<ref>{{Cite journal|last=McConnachie|first=Alan W.|date=2012-06-05|bibcode=2012AJ....144....4M|journal=The Astronomical Journal|language=en|volume=144|issue=1|pages=4|doi=10.1088/0004-6256/144/1/4|issn=0004-6256|arxiv=1204.1562|title=The Observed Properties of Dwarf Galaxies in and Around the Local Group|s2cid=118515618 }}</ref> | constellation name = [[Boötes]] | names = UGC 9128, [[David Dunlap Observatory Catalogue|DDO]] 187,<ref name="ddo1">{{cite journal|doi=10.1086/301157 |title=DDO 187: Do Dwarf Galaxies Have Extended, Old Halos? |date=2000 |last1=Aparicio |first1=Antonio |last2=Tikhonov |first2=Nikolay |last3=Karachentsev |first3=Igor |journal=The Astronomical Journal |volume=119 |issue=1 |pages=177–187 |arxiv=astro-ph/9909493 |bibcode=2000AJ....119..177A }}</ref> PGC 50961 }}
'''UGC 9128''' is a [[Dwarf galaxy|dwarf]] [[Irregular galaxy|irregular]] [[galaxy]] around 6.8–7.8 [[light-year|Mly]] (2.1–2.4 [[parsec|Mpc]]) away; it is thought to be in the [[Local Group]], although its membership is not certain.<ref name="telescope1">{{cite web |title=Dwarf galaxy: small but perfectly formed |url=https://esahubble.org/images/potw1117a/ |website=www.spacetelescope.org |access-date=8 August 2021 |language=en}}</ref><ref name="starburst1"/> The galaxy has a mass of about {{val|1.3|0.2|e=7|u={{solar mass}}}}, around 100 million [[stars]], and a diameter of around 3300 [[light-year|ly]].<ref name="starburst1"/><ref name="slate1">{{cite web |last1=Plait |first1=Phil |title=And the cottonball galaxies shall inherit the Universe |url=https://slate.com/technology/2011/04/and-the-cottonball-galaxies-shall-inherit-the-universe.html |website=Slate Magazine |access-date=8 August 2021 |language=en |date=25 April 2011}}</ref> It is therefore quite faint, and so was only discovered in the 20th century.<ref name="telescope1" />
UGC 9128 is around 2.7 [[light-year|Mly]] from [[GR 8 (galaxy)|GR 8]], which is its nearest neighbour.<ref name="ddo1" />
UGC 9128 is a [[starburst galaxy]], with the peak of star formation being 20–100 million years ago.<ref name="starburst1"/><ref name="ddo1" /> It is thought to have both a [[galactic halo|halo]] and [[galactic disc|disc]].<ref name="ddo1" />
== References == {{reflist}}
{{Boötes}}
[[Category:Dwarf irregular galaxies]] [[Category:Boötes]] [[Category:UGC objects|09128]] [[Category:Principal Galaxies Catalogue objects|50961]]
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