Wys bron van Portia (maan)

{{Inligtingskas Planeet
| bgcolour = #ffa812
| name = Portia
| image = [[Lêer:Uranus-Portia-Cressida-Ophelia-NASA.gif|240px]]
| mpc_name = Uranus XII
|discovery = yes
| discoverer = Stephen P. Synnott / [[Voyager 2]]
| discovered = 3 Januarie 1986
| semimajor = 66 097,265 ± 0,050 km<ref name="Jacobson 1998" />
| eccentricity = 0,00005 ± 0,00008<ref name="Jacobson 1998" />
| period = 0,5131959201 ± 0,0000000093 d<ref name="Jacobson 1998" />
| avg_speed = 9,37 km/s<ref name=calc group="nota">Bereken uit ander parameters.</ref>
| inclination = 0,05908 ± 0,039° (tot Uranus se ewenaar)<ref name="Jacobson 1998" />
| satellite_of = [[Uranus]]
| group = [[Herdersmaan]]
| dimensions = 156 × 126 × 126 km<ref name="Karkoschka, Voyager 2001" />
| mean_radius = 67,6 ± 4 km<ref name="Karkoschka, Voyager 2001" /><ref name="JPL-SSD-sat_phys" /><ref name="Williams 2007 nssdc" />
| surface_area = ~57 000 km²<ref name=calc group="nota"/>
| volume = ~1 300 000 km³<ref name=calc group="nota"/>
| mass = ~1,7{{e|18}} [[kilogram|kg]]<ref name=calc group="nota"/>
| density = ~1,3 g/cm³ (veronderstel)<ref name="JPL-SSD-sat_phys" />
| surface_grav = ~0,023 m/s<sup>2</sup><ref name=calc group="nota"/>
| escape_velocity = ~0,058 km/s<ref name=calc group="nota"/>
| rotation = Sinchronies<ref name="Karkoschka, Voyager 2001" />
| axial_tilt = 0<ref name="Karkoschka, Voyager 2001" />
| single_temperature = ~64 [[Kelvin|K]]
}}

'''Portia''' is ’n [[Natuurlike satelliet|binnemaan]] van [[Uranus]]. Dit is op 3&nbsp;Januarie 1986 ontdek op foto's wat deur [[Voyager 2|Voyager&nbsp;2]] geneem is en het die voorlopige naam '''S/1986&nbsp;U&nbsp;1''' gekry.<ref name="IAUC 4164" /> Dit is daarna genoem na Portia, die heldin in [[William Shakespeare]] se toneelstuk ''The Merchant of Venice''. Dit het ook die naam '''Uranus&nbsp;XII'''.<ref name="Gazetteer" />

Portia is die tweede grootste van die Portiagroep satelliete, wat ook [[Bianca (maan)|Bianca]], [[Desdemona (maan)|Desdemona]], [[Cressida (maan)|Cressida]], [[Juliet (maan)|Juliet]], [[Rosalind (maan)|Rosalind]], [[Kupido (maan)|Kupido]], [[Belinda (maan)|Belinda]] en [[Perdita (maan)|Perdita]] insluit.<ref name="Karkoschka, Hubble 2001" /> Dié mane het soortgelyke wentelbane en fotometriese eienskappe.<ref name="Karkoschka, Hubble 2001" /> Die grootste een van hulle is [[Puck (maan)|Puck]]. Die mane se wentelbane word al hoe kleiner weens gety-invloede en Portia sal eendag óf verbrokkel en ’n ring om Uranus vorm óf teen die planeet bots.

Buiten sy grootte van sowat 140&nbsp;km,<ref name="Karkoschka, Voyager 2001" /> wentelbaan<ref name="Jacobson 1998" /> en geometriese [[albedo]] van 0,08<ref name="Karkoschka, Hubble 2001" /> is feitlik niks oor Portia bekend nie.

Op die Voyager&nbsp;2-foto's lyk Portia soos ’n lang voorwerp, waarvan die lengteas na Uranus wys. Die verhouding van die asse is 0,8 ± 0,1.<ref name="Karkoschka, Voyager 2001" /> Die oppervlak het ’n [[grys]] kleur.<ref name="Karkoschka, Voyager 2001" /> Waarnemings met die [[Hubble-ruimteteleskoop]] en groot grondgebaseerde teleskope het bewyse gevind van waterys-absorpsie in Portia se [[Spektraallyn|spektrum]].<ref name="Karkoschka, Hubble 2001" /><ref name="Dumas Smith et al. 2003" />

==Galery==
<gallery class="center">
Lêer:Portia1.jpg|Portia soos op 23 Januarie 1986 gesien.
</gallery>

==Sien ook==
* [[Uranus se natuurlike satelliete]]

==Notas==
{{Reflist|group=nota}}

==Verwysings==
{{Verwysings|30em|verwysings=

<ref name="Jacobson 1998">
{{cite journal| doi = 10.1086/300263| last1 = Jacobson| first1 = R. A.| year = 1998| title = The Orbits of the Inner Uranian Satellites From Hubble Space Telescope and Voyager 2 Observations| journal = The Astronomical Journal| volume = 115| issue = 3| pages = 1195–1199| bibcode = 1998AJ....115.1195J| ref = harv}}
</ref>

<ref name="Karkoschka, Voyager 2001">
{{cite journal| doi = 10.1006/icar.2001.6597| last = Karkoschka| first = Erich| authorlink = Erich Karkoschka| year = 2001| title = Voyager's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites| journal = Icarus| volume = 151| issue = 1| pages = 69–77| bibcode = 2001Icar..151...69K| ref = {{sfnRef|Karkoschka, Voyager|2001}}}}
</ref>

<ref name="JPL-SSD-sat_phys">
{{cite web
| publisher = JPL (Solar System Dynamics)
| title = Planetary Satellite Physical Parameters
| date = 24 Oktober 2008
| url = http://ssd.jpl.nasa.gov/?sat_phys_par
| accessdate = 12 Desember 2008
}}
</ref>

<ref name="Williams 2007 nssdc">
{{cite web
| last = Williams
| first = Dr. David R.
| date = 23 November 2007
| title = Uranian Satellite Fact Sheet
| publisher = [[Nasa]] (National Space Science Data Center)
| url = http://nssdc.gsfc.nasa.gov/planetary/factsheet/uraniansatfact.html
| accessdate = 12 Desember 2008
}}
</ref>

<ref name="Karkoschka, Hubble 2001">
{{cite journal| doi = 10.1006/icar.2001.6596| last = Karkoschka| first = Erich| year = 2001| title = Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope| journal = Icarus| volume = 151| issue = 1| pages = 51–68| bibcode = 2001Icar..151...51K| ref = {{sfnRef|Karkoschka, Hubble|2001}}}}
</ref>

<ref name="IAUC 4164">
{{cite journal
 |last=Smith 
 |first=B.A. 
 |title=Satellites of Uranus 
 |journal=IAU Circular 
 |volume=4164 
 |date=16 Januarie 1986 
 |url=http://www.cbat.eps.harvard.edu/iauc/04100/04164.html#Item1 
 |accessdate=29 Oktober 2011 
 |url-status=dead 
 |archiveurl=https://web.archive.org/web/20111105040946/http://cbat.eps.harvard.edu/iauc/04100/04164.html 
 |archivedate=5 November 2011 
}}
</ref>

<ref name="Gazetteer">
{{cite web
| title = Planet and Satellite Names and Discoverers
| work = Gazetteer of Planetary Nomenclature
| publisher = USGS Astrogeology
| date = 21 Julie 2006
| url = http://planetarynames.wr.usgs.gov/Page/Planets
| accessdate = 6 Augustus 2006
}}
</ref>

<ref name="Dumas Smith et al. 2003">
{{cite journal| last1 = Dumas| first1 = Christophe| last2 = Smith| first2 = Bradford A.| last3 = Terrile| first3 = Richard J.| year = 2003| title = Hubble Space Telescope NICMOS Multiband Photometry of Proteus and Puck| journal = The Astronomical Journal| volume = 126| issue = 2| pages = 1080–1085| doi = 10.1086/375909| bibcode = 2003AJ....126.1080D| ref = {{sfnRef|Dumas Smith et al.|2003}}| doi-access = free}}
</ref>

}}

==Skakels==
{{vertaaluit| taalafk = en | il = Portia (moon)}}

{{Normdata}}

[[Kategorie:Mane van Uranus]]