View source for Callirrhoe (moon)

{{short description|Moon of Jupiter}}
{{Distinguish|Kallichore (moon)}}
{{Use dmy dates|date=November 2020}}
{{Infobox planet
 | name            = Callirrhoe
 | image           = S1999j1.jpg
 | image_scale      =
 | caption         = This discovery image of Callirrhoe taken by [[Spacewatch]] in October 1999
 | pronounced      = {{IPAc-en|k|ə|ˈ|l|ɪr|oʊ|iː}}<ref>{{cite book|author=Noah Webster|year=1884|title=A Practical Dictionary of the English Language}}</ref><ref>{{Dict.com|Pasiphae}}</ref>
 | adjective       = 
 | named_after     = [[Callirrhoe (daughter of Achelous)|Καλλιρρόη]] ''Kallirrhoê''
 | mpc_name        = Jupiter XVII
 | alt_names       = S/1999 J 1<br/>{{mp|1999 UX|18}}
 | discovery_ref   = <ref name="IAUC7460"/>
 | discoverer      = [[Spacewatch]]{{efn|The discovery is credited to the team of astronomers consisting of J. V. Scotti, T. B. Spahr, R. S. McMillan, J. A. Larson, J. Montani, A. E. Gleason, and T. Gehrels.<ref name="Gazetteer"/>}}
 | discovery_site  = [[Kitt Peak National Observatory]]
 | discovered      = 19 October 1999
 | earliest_precovery_date = 
 | satellite_of    = [[Jupiter]]
 | group           = [[Pasiphae group]]
 | orbit_ref       = <ref name="MPC115890"/>
 | epoch           = 27 April 2019 ([[Julian day|JD]] 2458600.5)
 | observation_arc = 17.54 [[Julian year (astronomy)|yr]] (6,406 days)
 | semimajor       = {{cvt|0.1643278|AU|km|lk=in}}
 | eccentricity    = 0.3095704
 | period          = –787.43 d
 | mean_anomaly    = 240.90203[[Degree (angle)|°]]
 | mean_motion     = {{Deg2DMS|0.45718492|sup=ms}} / day
 | inclination     = 147.99790° (to [[ecliptic]])
 | asc_node        = 352.75480°
 | arg_peri        = 68.21981°
 | mean_diameter   = {{val|9.6|1.3|u=km}}<ref name="Grav2015"/>
 | mass            = 
 | density         = <!-- assumed density of 2.6 g/cm3 from JPL -->
 | surface_grav    = 
 | escape_velocity = 
 | rotation        = 
 | albedo          = {{val|0.052|0.016}}<ref name="Grav2015"/>
 | magnitude       = 20.8<ref name="SheppardMoons"/>
 | abs_magnitude   = {{val|13.92|0.02}}<ref name="Grav2015"/>
}}

'''Callirrhoe''' ({{IPAc-en|k|ə|ˈ|l|ɪr|oʊ|.|iː}}; Greek: ''Καλλιρρόη''), also known as '''{{nowrap|Jupiter XVII}}''', is one of [[Jupiter]]'s outer [[natural satellite]]s. It is an [[irregular moon]] that orbits in a [[Retrograde and direct motion|retrograde]] direction. Callirrhoe was imaged by [[Spacewatch]] at [[Kitt Peak National Observatory]] from October 6 through November 4, 1999,<ref name=pr/> and originally designated as [[asteroid]] {{mp|1999 UX|18}}.<ref name="moon1999"/><ref>MPS 7418 (Minor Planet Circulars Supplement); not available on-line</ref> It was discovered to be in orbit around Jupiter by [[Timothy B. Spahr|Tim Spahr]] on July 18, 2000, and then given the designation '''{{nowrap|S/1999 J 1}}'''.<ref name="IAUC7460 "/><ref>[https://www.minorplanetcenter.net/mpec/K00/K00Y16.html MPEC 2000-Y16: ''S/1975 J 1 = S/2000 J 1, S/1999 J 1''] 2000-12-19 (discovery and ephemeris)</ref> It was the 17th confirmed moon of Jupiter.<ref name=pr/>

== Name ==
[[File:Callirrhoe-eso0025a.jpg|thumb|left|upright|Stack of three images taken by the [[Very Large Telescope|VLT]] in July 2000, showing Callirrhoe's movement relative to background stars]]
It was named in October 2002 after [[Callirrhoe (daughter of Achelous)|Callirrhoe]], daughter of the river god [[Achelous]], one of [[Zeus]]'s (Jupiter's) many conquests.<ref>[http://www.cbat.eps.harvard.edu/iauc/07900/07998.html IAUC 7998: Satellites of Jupiter] 2002 October 22 (naming the moon)</ref>

== Characteristics ==
Callirrhoe has an [[apparent magnitude]] of 20.8,<ref name="SheppardMoons"/> making it even fainter than [[dwarf planet]] [[Eris (dwarf planet)|Eris]] at magnitude 18.7.<ref name=Eris-AstDys>{{cite web |title=AstDys (136199) Eris Ephemerides |publisher=Department of Mathematics, University of Pisa, Italy |url=https://newton.spacedys.com/astdys/index.php?pc=1.1.3.0&n=Eris |accessdate=2009-03-16}}</ref> Jupiter is about 2.1 billion times brighter than Callirrhoe.{{efn|<math>\sqrt[5]{100^{13.92-\left(-9.4\right)}}\approx 2.13\times10^9</math>}}

Callirrhoe is about 9.6 kilometers in diameter,<ref name="Grav2015"/> and orbits Jupiter at an average distance of 24.1 million kilometers in 747.09 days, at an [[inclination]] of 141° to the [[ecliptic]] (140° to Jupiter's equator) with an [[eccentricity (orbit)|eccentricity]] of 0.28.  This object was probably captured long ago from a heliocentric orbit and the Sun's gravitational influence makes this orbit highly erratic.<ref name=pr/>

It belongs to the [[Pasiphae group]], irregular retrograde moons orbiting Jupiter at distances ranging between 22.8 and 24.1 million kilometers, and with [[inclination]]s ranging between 144.5° and 158.3°. However, while Pasiphae belongs to the grey color class (V=17.22 B−V=0.74, V−R=0.38), Callirrhoe falls under the light red color class (V=21.39 B−V=0.72, V−R=0.50), similarly to [[Megaclite]] and [[Sinope (moon)|Sinope]].<ref name="Grav2003">{{cite journal|last=Grav|first=Tommy|title=Photometric survey of the irregular satellites|journal=Icarus|volume=166|issue=1|date=2003|pages=33–45|doi=10.1016/j.icarus.2003.07.005|author2=Holman, M. J.|author3= Gladman, B. J.|author4= Aksnes, K.|bibcode=2003Icar..166...33G|arxiv = astro-ph/0301016 |s2cid=7793999}}</ref>

== Exploration ==
[[File:Callirrhoe - New Horizons.gif|thumb|left|upright|Callirrhoe imaged by the [[LORRI (New Horizons)|LORRI]] instrument aboard ''New Horizons'']]
As a navigation exercise, the ''[[New Horizons]]'' spacecraft imaged Callirrhoe on January 10, 2007.<ref>{{cite web|url=http://www.planetary.org/blogs/emily-lakdawalla/2007/jupiter_timeline.html|title=New Horizons Jupiter Encounter Timeline|website=www.planetary.org}}</ref>

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== Notes ==
{{notelist}}

== References ==
{{reflist|refs=

<ref name="MPC115890">{{cite web
  |title      = M.P.C. 115890
  |url        = https://minorplanetcenter.net/iau/ECS/MPCArchive/2019/MPC_20190827.pdf
  |work       = Minor Planet Circular
  |publisher  = Minor Planet Center
  |date       = 27 August 2019}}</ref>

<ref name="SheppardMoons">{{cite web
  |title      = Scott S. Sheppard - Jupiter Moons
  |url        = https://sites.google.com/carnegiescience.edu/sheppard/moons/jupitermoons
  |last       = Sheppard |first = Scott
  |work       = Department of Terrestrial Magnetism 
  |publisher  = Carnegie Institution for Science
  |accessdate = 26 November 2020}}</ref>

<ref name="IAUC7460">{{cite web
 |date         = 2000-07-20
 |title        = IAUC 7460: ''S/1999 J 1''
 |publisher    = IAU
 |author       = Brian G. Marsden
 |url          = http://www.cbat.eps.harvard.edu/iauc/07400/07460.html
 |access-date  = 2005-11-22
 |archive-url  = https://web.archive.org/web/20060426014719/http://cfa-www.harvard.edu/iauc/07400/07460.html#
 |archive-date = 2006-04-26
}}</ref>

<ref name="moon1999">{{cite web
  |title=New moon of Jupiter found
  |publisher=SpaceFlight Now (University of Arizona News Release)
  |url=http://spaceflightnow.com/news/n0007/21jovianmoon/
  |accessdate=2009-07-23}}</ref>

<ref name=pr>{{cite web
  |title=New Outer Satellite of Jupiter Discovered
  |publisher=[[Minor Planet Center]]
  |url=https://minorplanetcenter.net//iau/pressinfo/S1999J1.html
  |accessdate=2009-07-23}}</ref>

<ref name="Gazetteer">{{cite web
  |title      = Planet and Satellite Names and Discoverers
  |url        = https://planetarynames.wr.usgs.gov/Page/Planets#JovianSystem
  |work       = Gazetteer of Planetary Nomenclature
  |publisher  = USGS Astrogeology Science Center
  |accessdate = 26 November 2020}}</ref>

<ref name="Grav2015">{{cite journal
  |display-authors = etal
  |first1     = T. |last1 = Grav
  |first2     = J. M. |last2 = Bauer
  |first3     = A. K. |last3 = Mainzer
  |first4     = J. R. |last4 = Masiero
  |first5     = C. R. |last5 = Nugent
  |first6     = R. M. |last6 = Cutri
  |date       = August 2015
  |title      = NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn
  |journal    = The Astrophysical Journal
  |volume     = 809
  |issue      = 1
  |id         = 3
  |pages      = 9
  |doi        = 10.1088/0004-637X/809/1/3
  |bibcode    = 2015ApJ...809....3G|s2cid = 5834661 |url = https://authors.library.caltech.edu/61254/1/Grav_2015.pdf }}</ref>

}}

== External links ==
* [http://www.spaceref.com/news/viewnews.html?id=189 17th Moon of Jupiter Discovered] {{Webarchive|url=https://web.archive.org/web/20191018003020/http://www.spaceref.com/news/viewnews.html?id=189 |date=18 October 2019 }}
* [https://web.archive.org/web/20101001000947/http://spacewatch.lpl.arizona.edu/S1999J1.html Spacewatch S/1999 J 1]
* [http://www.nineplanets.org/1999j1.html Spacewatch discovery picture]

{{Moons of Jupiter}}

{{DEFAULTSORT:Callirrhoe (Moon)}}
[[Category:Pasiphae group]]
[[Category:Moons of Jupiter]]
[[Category:Irregular satellites]]
[[Category:Astronomical objects discovered in 1999]]
[[Category:Moons with a retrograde orbit]]