View source for Himalia (moon)

{{Use mdy dates|date=May 2019}}
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{{Infobox Planet
| name = Himalia
| image = Himalia.png
| bgcolour = #ffc0c0
| caption = Himalia as seen by [[Cassini-Huygens]]

| discoverer = [[Charles Dillon Perrine|C. D. Perrine]]
| discovered = December 3, 1904
| mean_orbit_radius = 11,460,000 [[kilometer|km]]<ref name="Jacobson 2000">{{cite journal| last=Jacobson| first=R. A.|title=The orbits of outer Jovian satellites| url=https://archive.org/details/sim_astronomical-journal_2000-11_120_5/page/2679|journal=Astronomical Journal| year=2000| volume=120| issue=5| pages=2679–2686|doi=10.1086/316817| bibcode=2000AJ....120.2679J| s2cid=120372170}}</ref>
| eccentricity = 0.16<ref name="Jacobson 2000"/>
| periapsis = 9,782,900 [[kilometer|km]]
| apoapsis = 13,082,000 [[kilometer|km]]
| period = 250.56 d (0.704 [[year|a]])<ref name="Jacobson 2000"/>
| avg_speed = 3.312&nbsp;km/s
| inclination = 27.50° (to the [[ecliptic]])<br/>29.59° (to Jupiter's equator)<ref name="Jacobson 2000"/>
| satellite_of = [[Jupiter (planet)|Jupiter]]

| mean_radius = 85&nbsp;km
| surface_area = ~90,800 [[square kilometer|km²]]
| volume = ~2,570,000 [[cubic kilometer|km³]]
| mass = 6.7{{e|18}} [[kilogram|kg]]
| density = 2.6&nbsp;g/cm³ (assumed)
| surface_grav = ~0.062 [[Acceleration|m/s<sup>2</sup>]] (0.006&nbsp;g)
| escape_velocity = ~0.100&nbsp;km/s
| sidereal_day = 7.782 h<ref name="Pilcher2012">{{cite journal | last = Pilcher | first = Frederick | author2=Mottola, Stefano | author3=Denk, Tilmann| title = Photometric lightcurve and rotation period of Himalia (Jupiter VI) |journal = Icarus | year = 2012 | volume = 219 | issue = 2 | pages = 741–742 | doi = 10.1016/j.icarus.2012.03.021 | bibcode = 2012Icar..219..741P }}</ref>
| albedo = 0.04<ref name="Porco2003">{{cite journal|last=Porco|first=Carolyn C. |display-authors = etal|title=Cassini Imaging of Jupiter's Atmosphere, Satellites, and Rings|journal=Science|volume=299|date=March 2003|issue=5612 |pages=1541–1547|doi=10.1126/science.1079462|pmid=12624258 |bibcode=2003Sci...299.1541P |s2cid=20150275 |url=https://resolver.caltech.edu/CaltechAUTHORS:20130128-105306147 }}</ref>
| single_temperature = ~124&nbsp;K
}}
'''Himalia''' is the biggest non-[[Sphere|spherical]] moon of [[Jupiter (planet)|Jupiter]]. It was found by [[Charles Dillon Perrine]] at the [[Lick Observatory]] on December 3, 1904.<ref>{{cite journal|title=Discovery of a Sixth Satellite of Jupiter|journal=Astronomical Journal| volume=24|issue=18|date=January 9, 1905| pages=154B|url=http://adsabs.harvard.edu//full/seri/AJ.../0024//0000154I002.html }};  {{cite journal|title=Sixth Satellite of Jupiter Confirmed (Himalaia)|url=http://adsabs.harvard.edu//full/seri/BHarO/0175//0000001.000.html|journal= Harvard College Observatory Bulletin|volume=175|date=January 25, 1905|page=1|bibcode=1905BHarO.175....1P|last1=Perrine|first1=C. D.}};  {{cite journal|last=Perrine|first=C. D.| url=http://adsabs.harvard.edu//full/seri/PASP./0017//0000022.000.html|title=Discovery of a Sixth Satellite to Jupiter|journal=Publications of the Astronomical Society of the Pacific|volume=17|year=1905|pages=22–23}};  {{cite journal|last=Perrine|first=C. D.| url=http://adsabs.harvard.edu//full/seri/AN.../0169//0000027.000.html|title=Orbits of the sixth and seventh satellites of Jupiter|journal=Astronomische Nachrichten|volume=169|year=1905|issue=3|pages=43–44|doi=10.1002/asna.19051690304|bibcode=1905AN....169...43P}}</ref> It is named after the [[nymph]] [[Himalia (mythology)|Himalia]] who bore three sons of [[Zeus]] (the Greek equivalent of [[Jupiter (mythology)|Jupiter]]).

==Name==
Himalia did not get its present name until 1975;<ref name="IAUC 2846">{{cite journal| last=Marsden|first=B. G.|title=Satellites of Jupiter|journal=IAUC Circular |volume=2846|date=October 7, 1974|url=http://cfa-www.harvard.edu/iauc/02800/02846.html}}</ref> before then, it was simply known as '''{{nowrap|Jupiter VI}}''' or '''Jupiter Satellite VI''', although calls for a full name appeared shortly after its and [[Elara (moon)|Elara]]'s discovery. A.C.D. Crommelin wrote in 1905,
<blockquote>Unfortunately the numeration of Jupiter's satellites is now in precisely the same confusion as that of Saturn's system was before the numbers were abandoned and names substituted. A similar course would seem to be advisable here; the designation V for the inner satellite was tolerated for a time, as it was considered to be in a class by itself; but it has now got companions, so that this subterfuge disappears. The substitution of names for numerals is certainly more poetic.<ref name="Crommelin">{{cite journal|last=Crommelin|first=A. C. D.| url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1905MNRAS..65..524C|title=Provisional Elements of Jupiter's Satellite VI|journal=Monthly Notices of the Royal Astronomical Society|volume=65|issue=5|pages=524–527|date=March 10, 1905|doi=10.1093/mnras/65.5.524|bibcode=1905MNRAS..65..524C}}</ref></blockquote>

The moon was sometimes called '''Hestia''',<ref name="Gaposchkin">{{cite book| last=Payne-Gaposchkin|first=Cecilia |author2=Katherine Haramundanis |title= Introduction to Astronomy | url=https://archive.org/details/introductiontoas0000payn|year=1970 |publisher= Prentice-Hall |location=Englewood Cliffs, N.J.|isbn=978-0-13-478107-5}}</ref> after the [[Hestia|Greek goddess]], from 1955 to 1975.

==Orbit==
It is the biggest member of the [[Himalia group|group that bears its name]], the moons orbiting between 11.4 and 13 million kilometers from Jupiter at an [[Orbital inclination|inclination]] of about 27.5°.<ref name="SheppardJewittPorco2004">{{cite book| last1 = Bagenal| first1 = Fran| last2 = Dowling| first2 = Timothy E.| last3 = McKinnon| first3 = William B.| title = Jupiter: The Planet, Satellites and Magnetosphere| url = https://archive.org/details/isbn_9780521818087| year = 2004| publisher = Cambridge University Press| isbn = 978-0-521-81808-7| pages = [https://archive.org/details/isbn_9780521818087/page/263 263]–280 }}</ref> The orbital elements are as of January 2000.<ref name="Jacobson 2000"/> They are changing a lot due to [[Solar]] and planetary [[perturbations]].

== Physical characteristics ==
A day on Himalia is only about 7 3/4&nbsp;hours long.<ref name="pilcher2012">{{cite journal | last = Pilcher | first = Frederick | author2=Mottola, Stefano | author3=Denk, Tilmann  | title = Photometric lightcurve and rotation period of Himalia (Jupiter VI) |journal = Icarus | date = 2012 | volume = 219 | issue = 2 | pages = 741–742 | doi = 10.1016/j.icarus.2012.03.021 |bibcode = 2012Icar..219..741P }}</ref> Himalia appears grey, like the other members of its group, similar to a [[C-type asteroid]].<ref name="Rettig2001">{{cite journal|title=Implied Evolutionary Differences of the Jovian Irregular Satellites from a BVR Color Survey|journal=Icarus| volume=154|year=2001|issue=2|pages=313–320|doi=10.1006/icar.2001.6715|bibcode=2001Icar..154..313R|last1=Rettig|first1=T.|last2=Walsh|first2=Kevin|last3=Consolmagno|first3=Guy}}</ref> Measurements by ''[[Cassini–Huygens|Cassini]]'' confirm a featureless [[electromagnetic spectrum|spectrum]], with a slight absorption at 3 μm which could indicate the presence of water.<ref name="Chamberlain">{{cite journal| title=Near-infrared spectroscopy of Himalia|journal=Icarus|volume=172|year=2004|pages=163–169|doi=10.1016/j.icarus.2003.12.016|last1=Chamberlain|first1=M.|last2=Brown|first2=Robert H.|issue=1|bibcode=2004Icar..172..163C}}</ref>

== Exploration ==
In November 2000, the [[Cassini–Huygens|Cassini]] [[spacecraft]], going to [[Saturn (planet)|Saturn]], made a number of pictures of Himalia, including photos from a distance as close as 4.4 million km. The moon covers only a few pixels, but seems to be a stretched object with axes 150 ± 20 and 120 ± 20&nbsp;km, close to the Earth-based estimations.<ref name=Porco2003/>

In February and March 2007, the [[New Horizons]] spacecraft to Pluto made a series of pictures of Himalia, culminating in photos from a distance of eight million km. Again, Himalia appears only a few pixels across.

==References==
{{reflist|2}}

==Other websites==
* [http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Himalia Himalia Profile] {{Webarchive|url=https://web.archive.org/web/20111227122307/http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Himalia |date=2011-12-27 }} by [http://solarsystem.nasa.gov NASA's Solar System Exploration]
* [http://www.ifa.hawaii.edu/~jewitt/irregulars.html David Jewitt pages]
* [http://www.ifa.hawaii.edu/~sheppard/satellites/jupsatdata.html Scott Sheppard pages]

{{Moons of Jupiter}}

[[Category:Jupiter's moons]]