{{Short description|Extremely faint candidate satellite galaxy of the Milky Way}} {{Infobox galaxy | image = [[File:Draco II.jpg|frameless||center]] | caption = Photograph of the Draco II satellite galaxy. | name = Draco II / Laevens 4 | epoch = [[Epoch (astronomy)#Julian years and J2000|J2000]] | ra = {{RA|15|52|47.6}}<ref name=SIMBAD>{{cite simbad|title=NAME Draco II|access-date=2025-04-07}}</ref> | dec = {{DEC|+64|33|55}}<ref name=SIMBAD/> | dist_ly = {{val|70.1|1.3}} [[lightyear|kly]]<br>({{val|21.5|0.4}} [[kiloparsec|kpc]])<ref name="longeard"/> | z = | appmag_v = | mass_light_ratio = {{val|2.7|0.5|0.8}}<ref name="martin"/> | stars = | half_light_radius_pc = | half_light_radius_arcminsec = | constellation name = [[Draco (constellation)|Draco]] | absmag_v={{val|-0.8|0.4|1}}<ref name="longeard"/> | names =Lae 4, Dra II |size=324 ly|type=dSph}}
'''Draco II / Leavens 4''' is a [[Dwarf galaxy|dwarf]] [[satellite galaxy]] orbiting the [[Milky Way]] discovered by the [[Pan-STARRS|Pan-STARRS1 3π survey]] in 2015.<ref name="martin">{{Cite journal |last1=Martin |first1=Nicolas F. |last2=Geha |first2=Marla |last3=Ibata |first3=Rodrigo A. |last4=Collins |first4=Michelle L. M. |last5=Laevens |first5=Benjamin P. M. |last6=Bell |first6=Eric F. |last7=Rix |first7=Hans-Walter |last8=Ferguson |first8=Annette M. N. |last9=Chambers |first9=Kenneth C. |last10=Wainscoat |first10=Richard J. |last11=Waters |first11=Christopher |date=2016-03-01 |title=Is Draco II one of the faintest dwarf galaxies? First study from Keck/DEIMOS spectroscopy |url=https://academic.oup.com/mnrasl/article/458/1/L59/2589548 |journal=Monthly Notices of the Royal Astronomical Society: Letters |volume=458 |issue=1 |pages=L59–L63 |doi=10.1093/mnrasl/slw013 |doi-access=free |issn=1745-3925|arxiv=1510.01326 }}</ref> Currently, it is both one of the nearest and dimmest galaxies known to astronomers. Analysis of its stars' distribution in [[Hertzsprung–Russell diagram|color–magnitude space]] show that Draco II is approximately 13.5 billion years old.<ref name="longeard">{{Cite journal |last1=Longeard |first1=Nicolas |last2=Martin |first2=Nicolas |last3=Starkenburg |first3=Else |last4=Ibata |first4=Rodrigo A |last5=Collins |first5=Michelle L M |last6=Geha |first6=Marla |last7=Laevens |first7=Benjamin P M |last8=Rich |first8=R Michael |last9=Aguado |first9=David S |last10=Arentsen |first10=Anke |last11=Carlberg |first11=Raymond G |last12=Côté |first12=Patrick |last13=Hill |first13=Vanessa |last14=Jablonka |first14=Pascale |last15=González Hernández |first15=Jonay I |date=2018-10-21 |title=Pristine dwarf galaxy survey – I. A detailed photometric and spectroscopic study of the very metal-poor Draco II satellite |url=https://academic.oup.com/mnras/article/480/2/2609/5060758 |journal=Monthly Notices of the Royal Astronomical Society |volume=480 |issue=2 |pages=2609–2627 |doi=10.1093/mnras/sty1986 |doi-access=free |issn=0035-8711|arxiv=1807.10655 }}</ref>
==References== {{reflist}} {{Milky Way}}
[[Category:Draco (constellation)]] [[Category:Extragalactic astronomy]] [[Category:Interacting galaxies]] [[Category:Dwarf galaxies]]