Themisto (moon): Difference between revisions
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{{Short description|Outer moon of Jupiter}} |
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{{Use dmy dates|date=November 2020}} |
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{{Infobox planet |
{{Infobox planet |
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| name = Themisto |
| name = Themisto |
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| image = S 2000 J 1.jpg |
| image = S 2000 J 1.jpg |
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| image_scale = |
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| image_size = 250 |
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| caption = Rediscovery images of Themisto taken in November 2000 |
| caption = Rediscovery images of Themisto taken by the [[UH88]] telescope in November 2000 |
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| pronounced = {{IPAc-en|θ| |
| pronounced = {{IPAc-en|θ|ə|ˈ|m|ɪ|s|t|oʊ}}<ref>Cf. 'Themista' in {{cite book|author=Noah Webster|year=1884|title=A Practical Dictionary of the English Language}}</ref> |
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| adjectives = Themistoan {{IPAc-en|θ|ɛ|m| |
| adjectives = Themistoan {{IPAc-en|θ|ɛ|m|ə|ˈ|s|t|oʊ|.|ə|n}}<ref>'Themis[t]oan' in {{cite book|author=James Hall|year=2015|title=Moons of the Solar System|page=82}}</ref> {{nowrap|Themistoian {{IPAc-en|θ|ɛ|m|ə|ˈ|s|t|oʊ|.|i|ə|n}}}} |
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| named_after = [[Themisto |
| named_after = [[Themisto|Θεμιστώ]] ''Themistō'' |
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| mpc_name = Jupiter XVIII |
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| alt_names = S/2000 J 1 |
| alt_names = S/2000 J 1<br/>S/1975 J 1 |
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| discoverer = [[Charles Kowal]]<small> (1975)</small><br> |
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| discovery_ref = <ref name="IAUC2845"/><ref name="IAUC7525"/> |
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[[Elizabeth Roemer]]<small> (1975)</small><br> |
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| discoverer = [[Charles T. Kowal]] {{small|(1975)}}<br/>[[Elizabeth Roemer|Elizabeth P. Roemer]] {{small|(1975)}}<br/>[[Scott S. Sheppard]] {{small|(2000)}}<br/>[[David C. Jewitt]] {{small|(2000)}}<br/>[[Yanga R. Fernández]] {{small|(2000)}}<br/>Eugene A. Magnier {{small|(2000)}} |
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[[Scott S. Sheppard]]<small> (2000)</small><br> |
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| discovery_site = [[Palomar Observatory]]<br/>[[Mauna Kea Observatory]] {{small|(rediscovery)}} |
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[[David C. Jewitt]]<small> (2000)</small><br> |
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| discovered = 30 September 1975<br/>21 November 2000 {{small|(rediscovery)}} |
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[[Yanga R. Fernández]]<small> (2000)</small><br> |
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| earliest_precovery_date = |
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[[Eugene A. Magnier]]<small> (2000)</small> |
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| discovered = September 30, 1975<br> |
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November 21, 2000<small> rediscovered</small> |
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| orbit_ref = <ref name="MPC110499"/> |
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| epoch = 23 March 2018 ([[Julian day|JD]] 2458200.5) |
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| observation_arc = 42.54 [[Julian year (astronomy)|yr]] (15,536 days) |
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| inclination = 43.08° |
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| eccentricity = 0. |
| eccentricity = 0.2522112 |
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| mean_anomaly = |
| mean_anomaly = 2.39396[[Degree (angle)|°]] |
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| mean_motion = {{Deg2DMS|2.77038036|sup=ms}} / day |
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| inclination = 45.28121° (to [[ecliptic]]) |
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| magnitude =21.0 |
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| physical_ref = |
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| mean_diameter = 9 km<ref name="SheppardMoons"/><br>16.4 km<ref name="EmelyanovEtAl2022"/> |
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| mass = 6.89{{e|14}} kg{{cn|date=March 2020}} |
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| mass = |
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| density = |
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| albedo = 0.04 (<i>assumed'')<ref name="SheppardJewitt2003">[[Scott S. Sheppard|Sheppard, S. S.]]; [[David C. Jewitt|Jewitt, D. C.]]; [http://www2.ess.ucla.edu/~jewitt/papers/JSATS/SJ2003.pdf ''An abundant population of small irregular satellites around Jupiter''], Nature, '''423''' (May 15, 2003), pp. 261–263</ref> |
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| surface_grav = |
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| single_temperature = ~124 K |
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| escape_velocity = |
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| rotation = |
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| albedo = 0.04 (assumed) |
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| magnitude = 21.0<ref name="SheppardMoons"/> |
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| abs_magnitude = 12.9<ref name="MPC110499"/><br>{{val|13.06|0.34}} (V)<ref name="EmelyanovEtAl2022"/> |
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}} |
}} |
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'''Themisto''' {{IPAc-en|θ| |
'''Themisto''' {{IPAc-en|θ|ə|ˈ|m|ɪ|s|t|oʊ}}, also known as '''{{nowrap|Jupiter XVIII}}''', is a small [[direct motion|prograde]] [[irregular satellite]] of [[Jupiter]]. It was discovered in 1975, subsequently lost, and rediscovered in 2000. |
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== Discovery and naming == |
== Discovery and naming == |
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[[File:Themisto-Holman-CFHT.gif|thumb|left|Themisto observed by the [[Canada-France-Hawaii Telescope]] on |
[[File:Themisto-Holman-CFHT.gif|thumb|left|Themisto observed by the [[Canada-France-Hawaii Telescope]] on 6 August 2000, several months before its rediscovery in November 2000]] |
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Themisto was first discovered by [[Charles T. Kowal]] and [[Elizabeth Roemer]] on |
Themisto was first discovered by [[Charles T. Kowal]] and [[Elizabeth Roemer]] on 30 September 1975, reported on 3 October 1975,<ref name="IAUC2845">{{cite web |author=Brian G. Marsden |url=http://www.cbat.eps.harvard.edu/iauc/02800/02845.html |title=IAUC 2845: Probable New Satellite of Jupiter |date=3 October 1975 |publisher=International Astronomical Union Central Bureau for Astronomical Telegrams}}</ref> and designated ''{{nowrap|S/1975 J 1}}''. However, not enough observations were made to establish an orbit and it was subsequently lost. |
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Themisto appeared as a footnote in astronomy textbooks into the 1980s. Then, in 2000, a seemingly new satellite was discovered by [[Scott S. Sheppard]], [[David C. Jewitt]], [[Yanga R. Fernández]] and |
Themisto appeared as a footnote in astronomy textbooks into the 1980s.{{cn|date=November 2020}} Then, in 2000, a seemingly new satellite was discovered by [[Scott S. Sheppard]], [[David C. Jewitt]], [[Yanga R. Fernández]] and Eugene A. Magnier, and was designated ''{{nowrap|S/2000 J 1}}''. It was soon confirmed that this was the same as the one observed in 1975.<ref name="IAUC7525">{{cite web |author=Brian G. Marsden |url=http://www.cbat.eps.harvard.edu/iauc/07500/07525.html |title=IAUC 7525: S/1975 J 1 = S/2000 J 1 |date=25 November 2000 |publisher=International Astronomical Union Central Bureau for Astronomical Telegrams}}</ref> This observation was immediately correlated with an observation on 6 August 2000, by the team of [[Brett J. Gladman]], [[John J. Kavelaars]], [[Jean-Marc Petit]], [[Hans Scholl (astronomer)|Hans Scholl]], [[Matthew J. Holman]], [[Brian G. Marsden]], [[Philip D. Nicholson]] and [[Joseph A. Burns]], which was reported to the [[Minor Planet Center]] but not published as an IAU Circular (IAUC).<ref name="MPEC-2000-Y16">{{cite web |url=http://www.minorplanetcenter.org/mpec/K00/K00Y16.html |title=MPEC 2000-Y16: S/1975 J 1 = S/2000 J 1, S/1999 J 1 |date=19 December 2000 |publisher=International Astronomical Union Minor Planet Center}}</ref> |
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In October 2002 it was officially named after [[ |
In October 2002 it was officially named after [[Themisto]],<ref>{{cite web |author=Daniel W. E. Green |url=http://www.cbat.eps.harvard.edu/iauc/07900/07998.html |title=IAUC 7998: Satellites of Jupiter |date=22 October 2002 |publisher=International Astronomical Union}}</ref> daughter of the river god [[Inachus]] and lover of [[Zeus]] (Jupiter) in [[Greek mythology]]. |
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== Characteristics == |
== Characteristics == |
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[[Image:TheIrregulars JUPITER GROUPS.svg|thumb|left|290px|Diagram illustrating Themisto's orbit (top left) among those of the other irregular satellites of Jupiter. The satellites above the horizontal axis are [[direct motion|prograde]], the satellites beneath it are [[retrograde motion|retrograde]]. The yellow segments extend from the [[apsis|pericentre]] to the [[apsis|apocentre]], showing the [[orbital eccentricity]]. ]] |
[[Image:TheIrregulars JUPITER GROUPS.svg|thumb|left|290px|Diagram illustrating Themisto's orbit (top left) among those of the other irregular satellites of Jupiter. The satellites above the horizontal axis are [[direct motion|prograde]], the satellites beneath it are [[retrograde motion|retrograde]]. The yellow segments extend from the [[apsis|pericentre]] to the [[apsis|apocentre]], showing the [[orbital eccentricity]]. ]] |
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Themisto's orbit is unusual: unlike most of [[Moons of Jupiter|Jupiter's moons]], which orbit in distinct groups, Themisto orbits alone. The moon is located midway between the [[Galilean moons]] and the first group of prograde irregular moons, |
Themisto's orbit is unusual: unlike most of [[Moons of Jupiter|Jupiter's moons]], which orbit in distinct groups, Themisto orbits alone. The moon is located midway between the [[Galilean moons]] and the first group of prograde irregular moons, the [[Himalia group]]. |
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Themisto is about {{cvt|9|km}} in diameter (assuming an [[albedo]] of 0.04).<ref name="SheppardMoons"/> While its true albedo could not be measured by [[NEOWISE]] due to poor timing of observations,<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|arxiv = 1505.07820 |bibcode = 2015ApJ...809....3G|s2cid = 5834661 |url = https://authors.library.caltech.edu/61254/1/Grav_2015.pdf }}</ref> it is known to have [[color index]] B−V=0.83, V−R=0.46, and V−I=0.94.<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> |
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Themisto is about 8 kilometers (5 miles) in diameter (assuming an [[albedo]] of 0.04).<ref name="SheppardJewitt2003"/> That figure can be used to find a surface area of between 200 and 380 square kilometers. |
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{{clear}} |
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== References == |
== References == |
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{{reflist |
{{reflist|refs= |
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<ref name="MPC110499">{{cite web |
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* {{cite web |title=Planetary Satellite Mean Orbital Parameters |url=http://ssd.jpl.nasa.gov/?sat_elem |publisher=JPL}} |
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|title = M.P.C. 110499 |
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|url = https://minorplanetcenter.net/iau/ECS/MPCArchive/2018/MPC_20180529.pdf |
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|work = Minor Planet Circular |
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|publisher = Minor Planet Center |
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|date = 29 May 2018}}</ref> |
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<ref name="SheppardMoons">{{cite web |
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|title = Scott S. Sheppard - Jupiter Moons |
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|last = Sheppard |first = Scott |
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|work = Department of Terrestrial Magnetism |
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|publisher = Carnegie Institution for Science |
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|access-date = 26 November 2020}}</ref> |
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<ref name="EmelyanovEtAl2022">{{cite journal |last1=Emelyanov |first1=N. V. |last2=Varfolomeev |first2=M. I. |last3=Lainey |first3=V. |date=24 March 2022 |title=New ephemerides of outer planetary satellites |journal=Monthly Notices of the Royal Astronomical Society |volume=512 |issue=2 |pages=2044–2050 |doi=10.1093/mnras/stac586 |doi-access=free|url=https://hal-insu.archives-ouvertes.fr/insu-03718982/file/stac586.pdf }}</ref> |
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}} |
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== External links == |
== External links == |
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* [https://web.archive.org/web/20060901072706/http://www.ifa.hawaii.edu/~jewitt/irregulars.html David Jewitt's pages] |
* [https://web.archive.org/web/20060901072706/http://www.ifa.hawaii.edu/~jewitt/irregulars.html David Jewitt's pages] |
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* [http://home.dtm.ciw.edu/users/sheppard/satellites/jupsatdata.html Jupiter's Known Satellites] (by [[Scott S. Sheppard]]) |
* [http://home.dtm.ciw.edu/users/sheppard/satellites/jupsatdata.html Jupiter's Known Satellites] {{Webarchive|url=https://web.archive.org/web/20150318034833/http://home.dtm.ciw.edu/users/sheppard/satellites/jupsatdata.html |date=18 March 2015 }} (by [[Scott S. Sheppard]]) |
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{{Jupiter}} |
{{Jupiter}} |
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{{Moons of Jupiter}} |
{{Moons of Jupiter}} |
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[[Category:Irregular satellites]] |
[[Category:Irregular satellites]] |
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[[Category:Discoveries by Charles T. Kowal]] |
[[Category:Discoveries by Charles T. Kowal]] |
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[[Category:Discoveries by Elizabeth P. Roemer]] |
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[[Category:Discoveries by Scott S. Sheppard]] |
[[Category:Discoveries by Scott S. Sheppard]] |
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[[Category: |
[[Category:Discoveries by David C. Jewitt]] |
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[[Category:Discoveries by Yanga R. Fernandez]] |
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[[Category:Discoveries by Eugene A. Magnier]] |
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[[Category:Astronomical objects discovered in 1975|19750930]] |
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[[Category:Astronomical objects discovered in 2000|20001121]] |
[[Category:Astronomical objects discovered in 2000|20001121]] |
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[[Category:Moons with a prograde orbit]] |
Latest revision as of 16:32, 27 July 2024
Discovery[1][2] | |
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Discovered by | Charles T. Kowal (1975) Elizabeth P. Roemer (1975) Scott S. Sheppard (2000) David C. Jewitt (2000) Yanga R. Fernández (2000) Eugene A. Magnier (2000) |
Discovery site | Palomar Observatory Mauna Kea Observatory (rediscovery) |
Discovery date | 30 September 1975 21 November 2000 (rediscovery) |
Designations | |
Designation | Jupiter XVIII |
Pronunciation | /θəˈmɪstoʊ/[3] |
Named after | Θεμιστώ Themistō |
S/2000 J 1 S/1975 J 1 | |
Adjectives | Themistoan /θɛməˈstoʊ.ən/[4] Themistoian /θɛməˈstoʊ.iən/ |
Orbital characteristics[5] | |
Epoch 23 March 2018 (JD 2458200.5) | |
Observation arc | 42.54 yr (15,536 days) |
0.0494401 AU (7,396,130 km) | |
Eccentricity | 0.2522112 |
+129.95 d | |
2.39396° | |
2° 46m 13.369s / day | |
Inclination | 45.28121° (to ecliptic) |
192.64162° | |
241.25168° | |
Satellite of | Jupiter |
Group | (own group) |
Physical characteristics | |
9 km[6] 16.4 km[7] | |
Albedo | 0.04 (assumed) |
21.0[6] | |
12.9[5] 13.06±0.34 (V)[7] | |
Themisto /θəˈmɪstoʊ/, also known as Jupiter XVIII, is a small prograde irregular satellite of Jupiter. It was discovered in 1975, subsequently lost, and rediscovered in 2000.
Discovery and naming
[edit]Themisto was first discovered by Charles T. Kowal and Elizabeth Roemer on 30 September 1975, reported on 3 October 1975,[1] and designated S/1975 J 1. However, not enough observations were made to establish an orbit and it was subsequently lost.
Themisto appeared as a footnote in astronomy textbooks into the 1980s.[citation needed] Then, in 2000, a seemingly new satellite was discovered by Scott S. Sheppard, David C. Jewitt, Yanga R. Fernández and Eugene A. Magnier, and was designated S/2000 J 1. It was soon confirmed that this was the same as the one observed in 1975.[2] This observation was immediately correlated with an observation on 6 August 2000, by the team of Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Philip D. Nicholson and Joseph A. Burns, which was reported to the Minor Planet Center but not published as an IAU Circular (IAUC).[8]
In October 2002 it was officially named after Themisto,[9] daughter of the river god Inachus and lover of Zeus (Jupiter) in Greek mythology.
Characteristics
[edit]Themisto's orbit is unusual: unlike most of Jupiter's moons, which orbit in distinct groups, Themisto orbits alone. The moon is located midway between the Galilean moons and the first group of prograde irregular moons, the Himalia group.
Themisto is about 9 km (5.6 mi) in diameter (assuming an albedo of 0.04).[6] While its true albedo could not be measured by NEOWISE due to poor timing of observations,[10] it is known to have color index B−V=0.83, V−R=0.46, and V−I=0.94.[11]
References
[edit]- ^ a b Brian G. Marsden (3 October 1975). "IAUC 2845: Probable New Satellite of Jupiter". International Astronomical Union Central Bureau for Astronomical Telegrams.
- ^ a b Brian G. Marsden (25 November 2000). "IAUC 7525: S/1975 J 1 = S/2000 J 1". International Astronomical Union Central Bureau for Astronomical Telegrams.
- ^ Cf. 'Themista' in Noah Webster (1884). A Practical Dictionary of the English Language.
- ^ 'Themis[t]oan' in James Hall (2015). Moons of the Solar System. p. 82.
- ^ a b "M.P.C. 110499" (PDF). Minor Planet Circular. Minor Planet Center. 29 May 2018.
- ^ a b c Sheppard, Scott. "Scott S. Sheppard - Jupiter Moons". Department of Terrestrial Magnetism. Carnegie Institution for Science. Retrieved 26 November 2020.
- ^ a b Emelyanov, N. V.; Varfolomeev, M. I.; Lainey, V. (24 March 2022). "New ephemerides of outer planetary satellites" (PDF). Monthly Notices of the Royal Astronomical Society. 512 (2): 2044–2050. doi:10.1093/mnras/stac586.
- ^ "MPEC 2000-Y16: S/1975 J 1 = S/2000 J 1, S/1999 J 1". International Astronomical Union Minor Planet Center. 19 December 2000.
- ^ Daniel W. E. Green (22 October 2002). "IAUC 7998: Satellites of Jupiter". International Astronomical Union.
- ^ Grav, T.; Bauer, J. M.; Mainzer, A. K.; Masiero, J. R.; Nugent, C. R.; Cutri, R. M.; et al. (August 2015). "NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn" (PDF). The Astrophysical Journal. 809 (1): 9. arXiv:1505.07820. Bibcode:2015ApJ...809....3G. doi:10.1088/0004-637X/809/1/3. S2CID 5834661. 3.
- ^ Grav, Tommy; Holman, M. J.; Gladman, B. J.; Aksnes, K. (2003). "Photometric survey of the irregular satellites". Icarus. 166 (1): 33–45. arXiv:astro-ph/0301016. Bibcode:2003Icar..166...33G. doi:10.1016/j.icarus.2003.07.005. S2CID 7793999.
External links
[edit]- David Jewitt's pages
- Jupiter's Known Satellites Archived 18 March 2015 at the Wayback Machine (by Scott S. Sheppard)
- "MPC: Natural Satellites Ephemeris Service". International Astronomical Union Minor Planet Center.
- "Planetary Satellite Mean Orbital Parameters". JPL.
- Moons of Jupiter
- Irregular satellites
- Discoveries by Charles T. Kowal
- Discoveries by Elizabeth P. Roemer
- Discoveries by Scott S. Sheppard
- Discoveries by David C. Jewitt
- Discoveries by Yanga R. Fernandez
- Discoveries by Eugene A. Magnier
- Astronomical objects discovered in 1975
- Astronomical objects discovered in 2000
- Moons with a prograde orbit