Portia (moon)

Template:Short description {{#invoke:infobox|infoboxTemplate | class = vcard | titleclass = fn org | title = Portia | image = {{#invoke:InfoboxImage|InfoboxImage|image=Uranus-Portia-Cressida-Ophelia-NASA.gif|upright={{#if:||1.1}}|alt=}} | caption = | headerstyle = {{#if:|background-color:|background-color:#E0CCFF}} | labelstyle = max-width:{{#if:||11em}}; | autoheaders = y

| header1 = Discovery

| label2 = Discovered by | data2 = Stephen P. Synnott / Voyager 2 | label3 = Discovery site | data3 = | label4 = Discovery date | data4 = January 3, 1986 | label5 = Template:Longitem | data5 =

| header10 = {{#if:|Designations|Designations}}

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| header20 = Orbital characteristics{{#ifeq:|yes| (barycentric)}}<ref name="Jacobson 1998" />

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| header60 = Proper orbital elements

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({{#expr:365.25*360/1 round 3}} d) }} | label66 = Template:Longitem | data66 = {{#if:|{{{perihelion_rate}}} arcsecTemplate:\yr }} | label67 = Template:Longitem | data67 = {{#if:|{{{node_rate}}} arcsecTemplate:\yr}}

| header70 = Template:Anchor{{#if:| Physical characteristics|Physical characteristics}}

| label71 = Dimensions | data71 = 156 × 126 × 126 km<ref name="Karkoschka, Voyager 2001" />Template:Refn | label72 = Template:Longitem | data72 = | label73 = Template:Longitem | data73 = | label74 = Template:Longitem | data74 = | label75 = Template:Longitem | data75 = | label76 = Flattening | data76 = | label77 = Circumference | data77 = | label78 = Template:Longitem | data78 = ~58 000 km²Template:Efn | label79 = Volume | data79 = Template:Val<ref name = "FrenchEtAl2024"/> | label80 = Mass | data80 = Template:Val<ref name = "FrenchEtAl2024"/> | label81 = Template:Longitem | data81 = ≥0.57 g/cm³<ref name = "FrenchEtAl2024"/>
~0.90 g/cm³ (assumed) | label82 = Template:Longitem | data82 = ~Template:Gr–Template:Gr m/s²Template:Efn | label83 = Template:Longitem | data83 = | label84 = Template:Longitem | data84 = ~Template:V2–Template:V2 km/sTemplate:Efn | label85 = Template:Longitem | data85 = synchronous<ref name="Karkoschka, Voyager 2001" /> | label86 = Template:Longitem | data86 = | label87 = Template:Longitem | data87 = | label88 = Template:Longitem | data88 = zero<ref name="Karkoschka, Voyager 2001" /> | label89 = Template:Longitem | data89 = | label90 = Template:Longitem | data90 = | label91 = Template:Longitem | data91 = | label92 = Template:Longitem | data92 = | label93 = {{#if: |Template:Longitem |Albedo}} | data93 = Template:Ubl | label94 = Temperature | data94 = ~64 KTemplate:Efn

| data100 = {{#if:|

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Surface temp.	min	mean	max
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| header110 = Atmosphere

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Portia is an inner satellite of Uranus. It was discovered from the images taken by Voyager 2 on 3 January 1986, and was given the temporary designation S/1986 U 1.<ref name="IAUC 4164" /> The moon is named after Portia, the heroine of William Shakespeare's play The Merchant of Venice. It is also designated Uranus XII.<ref name="Gazetteer" />

Portia is the second-largest inner satellite of Uranus after Puck. The Portian orbit, which lies inside Uranus's synchronous orbital radius, is slowly decaying due to tidal deceleration. The moon will one day either break up into a planetary ring or hit Uranus.Template:Cn

It is the namesake of a group of satellites called the Portia group, which includes Bianca, Cressida, Desdemona, Juliet, Rosalind, Cupid, Belinda, and Perdita.<ref name="Karkoschka, Hubble 2001" /> These satellites have similar orbits and photometric properties.<ref name="Karkoschka, Hubble 2001" />

Little is known about Portia beyond its dimensions of about 156 × 126 km,<ref name="Karkoschka, Voyager 2001" /> orbit,<ref name="Jacobson 1998" /> and geometric albedo of about 0.08.<ref name="Karkoschka, Hubble 2001" />

In Voyager 2 imagery, Portia appears as an elongated object whose major axis points towards Uranus. The ratio of axes of the Portia's prolate spheroid is 0.8 ± 0.1.<ref name="Karkoschka, Voyager 2001" /> Its surface is grey in color.<ref name="Karkoschka, Voyager 2001" /> Observations with Hubble Space Telescope and large terrestrial telescopes found water ice absorption features in the spectrum of Portia.<ref name="Karkoschka, Hubble 2001" /><ref name="Dumas Smith et al. 2003" /> Observations with James Webb Space Telescope have also found evidence for water ice or hydrated minerals on Portia's surface, and have also confirmed that Portia group members Juliet, Belinda, and Cressida have roughly similar spectra to Portia.<ref>Template:Cite journal</ref>

Gallery

• Portia1.jpg

  Portia seen on January 23, 1986.

See also

• Moons of Uranus

External links

• Portia Profile by NASA's Solar System Exploration
• Uranus' Known Satellites (by Scott S. Sheppard)

Template:Uranus {{#invoke:Navbox|navbox}} Template:Solar System moons (compact)