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Sinope (moon)

Sinope photographed by the Haute-Provence Observatory on 14 August 1998
Discovery [1]
Discovered byS. B. Nicholson
Discovery date21 July 1914
Jupiter IX
Named after
Σινώπη Sinōpē
AdjectivesSinopean[4] /snəˈpən/[5]
Orbital characteristics[6]
23939000 km
−724.5 day
Satellite ofJupiter
Physical characteristics
Mean diameter
~38 km[7][8]
Mass7.5×1016 kg[citation needed]
Mean density
2.6 g/cm3 (assumed)[7]
~ 0.014 m/s2 (0.001 g)
~ 0.023 km/s
Temperature~ 124 K

Sinope /sɪˈnp/ is a retrograde irregular satellite of Jupiter discovered by Seth Barnes Nicholson at Lick Observatory in 1914,[1] and is named after Sinope of Greek mythology.

Sinope did not receive its present name until 1975;[10][11] before then, it was simply known as Jupiter IX. It was sometimes called "Hades"[12] between 1955 and 1975.

Sinope was the outermost known moon of Jupiter until the discovery of Megaclite in 2000. The most distant moon of Jupiter now known is S/2003 J 2.


Pasiphae group.

Sinope orbits Jupiter on a high-eccentricity and high-inclination retrograde orbit. Its orbit is continuously changing due to solar and planetary perturbations.[13] Sinope is believed to belong to the Pasiphae group of retrograde irregular moons.[8] However, given its mean inclination and different colour, Sinope could be also an independent object, captured independently, unrelated to the collision and break-up at the origin of the group.[14] The diagram illustrates Sinope's orbital elements in relation to other satellites of the group.

Sinope is also known to be in a secular resonance with Jupiter, similar to Pasiphae. However, Sinope can drop out of this resonance and has periods of both resonant and non-resonant behaviour in time scales of 107 years.[15]

Physical characteristics

Sinope has an estimated diameter of 38 km (assuming an albedo of 0.04)[8] Sinope is red (colour indices B−V=0.84, R−V=0.46),[14] unlike Pasiphae, which is grey.

Sinope's infrared spectrum is similar to those of D-type asteroids but different from that of Pasiphae.[16] These dissimilarities of the physical parameters suggest a different origin from the core members of the group.

See also


  1. ^ a b Nicholson, S. B. (1914). "Discovery of the Ninth Satellite of Jupiter". Publications of the Astronomical Society of the Pacific. 26: 197–198. Bibcode:1914PASP...26..197N. doi:10.1086/122336. PMC 1090718.
  2. ^ "Sinope". Unabridged. Random House.
  3. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  4. ^ Sergey Vnukov (2010) "Sinopean Amphorae of the Roman Period", Ancient Civilizations from Scythia to Siberia 16
  5. ^ Hector Stuart (1876) Ben Nebo, and Other Poems, p. 22
  6. ^ S.S. Sheppard (2019), Moons of Jupiter, Carnegie Science, on line
  7. ^ a b c d "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). 19 February 2015. Retrieved 28 February 2020.
  8. ^ a b c d Sheppard, S. S.; and Jewitt, D. C.; An Abundant Population of Small Irregular Satellites Around Jupiter, Nature, Vol. 423 (May 2003), pp. 261-263
  9. ^ "M.P.C. 111777" (PDF). Minor Planet Circular. Minor Planet Center. 25 September 2018. Retrieved 28 February 2020.
  10. ^ Nicholson, S. B. (April 1939). "The Satellites of Jupiter". Publications of the Astronomical Society of the Pacific. 51 (300): 85–94. Bibcode:1939PASP...51...85N. doi:10.1086/125010. (in which he declines to name the recently discovered satellites (pp. 93–94))
  11. ^ IAUC 2846: Satellites of Jupiter 1974 October (naming the moon)
  12. ^ Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-13-478107-4.
  13. ^ Jacobson, R. A. (2000). "The orbits of outer Jovian satellites" (PDF). Astronomical Journal. 120 (5): 2679–2686. Bibcode:2000AJ....120.2679J. doi:10.1086/316817.
  14. ^ a b Grav, T.; Holman, M. J.; Gladman, B. J.; and Aksnes, K.; Photometric Survey of the Irregular Satellites, Icarus, Vol. 166 (2003), pp. 33-45
  15. ^ Nesvorný, D.; Beaugé, C. & Dones, L. (2004). "Collisional Origin of Families of Irregular Satellites". The Astronomical Journal. 127 (3): 1768–1783. Bibcode:2004AJ....127.1768N. doi:10.1086/382099.
  16. ^ Grav, T.; Holman, M. J. (2004). "Near-Infrared Photometry of the Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal. 605 (2): L141–L144. arXiv:astro-ph/0312571. Bibcode:2004ApJ...605L.141G. doi:10.1086/420881.

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