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22 Kalliope

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22 Kalliope
Kalliope and satelliteLinusas seen by theW.M. Keck II telescopein 2010
Discovery
Discovered byJohn Russell Hind
Discovery date16 November 1852
Designations
(22) Kalliope
Pronunciation/kəˈl.əpi/kə-LY-ə-pee[1]
Named after
ΚαλλιόπηKalliopē
Main belt
AdjectivesKalliopean/kəˌl.əˈpən/kə-LY-ə-PEE-ən
Orbital characteristics[2]
Epoch23 July 2010 (JD2455400.5)
Aphelion479.98Gm(3.2085AU)
Perihelion391.03 Gm (2.6139 AU)
435.09 Gm (2.9112 AU)
Eccentricity0.10213
1814.3 d (4.97yr)
282.54°
Inclination13.703°
66.17°
355.03°
KnownsatellitesLinus
Physical characteristics
Dimensions235 km × 144 km × 124 km[3]
190 km × 125 km[4]
Flattening0.41[a]
Mass(7.7±0.4)×1018kg[5]
(8.16±0.26)×1018kg[3]
7.36×1018kg[6]
(6.30±0.50)×1018kg[7]
  • 4.36±0.50 g/cm3[5]
  • 3.35±0.33 g/cm3[3]
  • 2.37±0.40 g/cm3[6]
  • 2.03±0.16 g/cm3[7]
0.17285 days (4.1483 h)[2]
0.198[5]
0.17[3]
0.166 ± 0.005[2]
6.81[2]

22 Kalliope(/kəˈl.əpi/;kə-LY-ə-pee) is a largeM-type asteroidfrom theasteroid beltdiscovered byJ. R. Hindon 16 November 1852. It is named afterCalliope,theGreekMuseofepic poetry.It is orbited by a small moon namedLinus.

Characteristics

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VLT image of Kalliope

Kalliope is somewhat elongated, approximately 166 km indiameter,[3]and slightly asymmetric, as evidenced by resolved images taken with theVLTat theEuropean Southern Observatory.This new diameter, which was measured by observing mutual eclipses of Kalliope and Linus, is 8% smaller than that calculated fromIRASobservations.[3]

The spectrum of Kalliope is anM-type,indicating that its surface may be partially composed ofironnickelmetal. The asteroid's density is about 3.4 g/cm3.[3]Since the asteroid is likely to be arubble pile,accounting for a possible porosity of 20–40% leads to the material density of 4.2–5.8 g/cm3,which means that Kalliope is probably made of a mixture of metal withsilicates.[3]Spectroscopic studies have shown, however, evidence ofhydratedminerals[9]and silicates,[10]which indicate rather a stony surface composition. Kalliope also has a low radar albedo,[6]which is inconsistent with a purely metallic surface.

Lightcurve analysis indicates that Kalliope's pole most likely points towardsecliptic coordinates(β, λ) = (−23°, 20°) with a 10° uncertainty,[11][7]which gives Kalliope anaxial tiltof 103°. Kalliope's rotation is then slightly retrograde.

Between 2004 and 2021, 22 Kalliope has been observed tooccultfifteen stars.

Satellite

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Kalliope has one known natural satellite, called Linus or (22) Kalliope I Linus. It is quite large – about 28 km in diameter – and would be a sizeable asteroid by itself. It orbits about 1100 km from the center of Kalliope, equivalent to about 13.2 Kalliope radii.[3]Linus was discovered on 29 August 2001 byJean-Luc MargotandMichael E. Brown,while another team led by William Merline also independently detected the moon 3 days later.[6][7]

First stellar occultation

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On 7 November 2006, the first stellar occultation by the satellite of an asteroid (Linus) was successfully observed by a group of Japanese observers[4]according to a prediction that was made just one day before by Berthier et al.[12]based on more than 5 years of regular observations of Kalliope binary system usingadaptive opticssystems on ground-based telescopes. The observedchordsof Linus give a unique opportunity to estimate the size of the moonlet which was estimated to 20–28 km.

Notes

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  1. ^Flattening derived from the maximum aspect ratio (c/a):,where (c/a) =0.59±0.02.[5]

References

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  1. ^"calliope".Oxford English Dictionary(Online ed.).Oxford University Press.(Subscription orparticipating institution membershiprequired.)
  2. ^abcdefg"JPL Small-Body Database Browser: 22 Kalliope"(2010-06-02 last obs).Retrieved22 July2010.
  3. ^abcdefghijDescamps, P.; Marchis, F.; et al. (2008). "New determination of the size and bulk density of the binary asteroid 22 Kalliope from observations of mutual eclipses".Icarus.196(2): 578–600.arXiv:0710.1471.Bibcode:2008Icar..196..578D.doi:10.1016/j.icarus.2008.03.014.S2CID118437111.
  4. ^abM. Sôma, et al. (2006). "'Occultation by Kalliope (22) and its satellite Linus ".Central Bureau Electronic Telegrams.732:1.Bibcode:2006CBET..732....1S.
  5. ^abcdeVernazza, P.; et al. (October 2021)."VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis".Astronomy & Astrophysics.654:A56.Bibcode:2021A&A...654A..56V.doi:10.1051/0004-6361/202141781.hdl:10261/263281.S2CID239104699.
  6. ^abcdeJ.L. Margot & M.E. Brown (2003). "A Low-Density M-type Asteroid in the Main Belt".Science.300(5627): 1939–1942.Bibcode:2003Sci...300.1939M.doi:10.1126/science.1085844.PMID12817147.S2CID5479442.
  7. ^abcdeF. Marchis (2003). "A three-dimensional solution for the orbit of the asteroidal satellite of 22 Kalliope".Icarus.165(1): 112–120.Bibcode:2003Icar..165..112M.doi:10.1016/S0019-1035(03)00195-7.
  8. ^"EAR-A-5-DDR-TAXONOMY-V6.0".Planetary Data System.Archived fromthe originalon 17 December 2015.Retrieved16 April2018.
  9. ^A.S. Rivkin (2000). "The nature of M-class asteroids from 3-micron observations".Icarus.145(2): 351–368.Bibcode:2000Icar..145..351R.doi:10.1006/icar.2000.6354.
  10. ^D.F. Lupishko (1982). "UBV photometry of the M-type asteroids 16 Psyche and 22 Kalliope".Solar System Research.16:75.Bibcode:1982AVest..16..101L.
  11. ^M. Kaasalainen (2002)."Models of Twenty Asteroids from Photometric Data"(PDF).Icarus.159(2): 369–395.Bibcode:2002Icar..159..369K.doi:10.1006/icar.2002.6907.
  12. ^J. Berthier, et al. (2004). "'Prediction of stellar occultations by satellite of asteroids ".AAS/Division for Planetary Sciences Meeting Abstracts #36.32(23): 1142.Bibcode:2004DPS....36.3223B.
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