Sinope (moon)
| Discovery | |
|---|---|
| Discovered by | S. B. Nicholson |
| Discovery date | July 21, 1914 |
| Orbital characteristics | |
| Periapsis | 18,237,600 km |
| Apoapsis | 30,191,200 km |
| Mean orbit radius | 23,540,000 km[1] |
| Eccentricity | 0.25[1] |
| Orbital period | 724.1 d (1.95 a)[1] |
| Average orbital speed | 2.252 km/s |
| Inclination | 128.11° (to the ecliptic) 153.12° (to Jupiter's equator)[1] |
| Satellite of | Jupiter |
| Physical characteristics | |
| Mean radius | ~19 km |
| Volume | ~28,700 km³ |
| Mass | 7.5×1016 kg |
| Mean density | 2.6 g/cm³ (assumed) |
| Equatorial surface gravity | 0.014 m/s2 (0.001 g) |
| Escape velocity | ~0.023 km/s |
Sinope is a non-spherical moon of Jupiter. It was found by Seth Barnes Nicholson at Lick Observatory in 1914,[2] and is named after Sinope of Greek mythology.
Sinope did not get its present name until 1975[3][4]; before then, it was simply known as Jupiter IX. It was sometimes called "Hades"[5] between 1955 and 1975.
Sinope was the farthest known moon of Jupiter until the discovery of Megaclite in 2000. The farthest moon of Jupiter now known is S/2003 J 2.
Contents |
Orbit [change]
Sinope orbits Jupiter on a high eccentricity and high inclination retrograde orbit. The orbital elements are as of January 2000.[1] They are changing a lot due to Solar and planetary perturbations. It is often believed to belong to the Pasiphaë group.[6] 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.[7] The diagram illustrates Sinope's orbital elements in relation to other moons of the group.
Physical characteristics [change]
Sinope has an estimated diameter of 38 km (assuming an albedo of 0.04)[6] The moon is red[7] unlike Pasiphae which is grey.
Its infrared spectrum is similar to D-type asteroids also different from Pasiphae.[8] These dissimilarities of the physical parameters suggest a different origin from the core members of the group.
References [change]
- ↑ 1.0 1.1 1.2 1.3 1.4 Jacobson, R. A. (2000). "The Orbits of the Outer Jovian Satellites". Astronomical Journal 120: pp. 2679-2686. doi:10.1086/316817. http://www.journals.uchicago.edu/AJ/journal/issues/v120n5/200233/200233.web.pdf.
- ↑ Nicholson, S. B. (1914). "Discovery of the Ninth Satellite of Jupiter". Publications of the Astronomical Society of the Pacific 26: pp. 197-198. http://adsabs.harvard.edu//full/seri/PASP./0026//0000197.000.html.
- ↑ Nicholson, S. B. (April 1939). "The Satellites of Jupiter". Publications of the Astronomical Society of the Pacific 51 (300): pp. 85–94. http://adsabs.harvard.edu//full/seri/PASP./0051//0000093.000.html. (in which he declines to name the recently discovered satellites (pp. 93–94))
- ↑ IAUC 2846: Satellites of Jupiter 1974 October 7 (naming the moon)
- ↑ Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-134-78107-4.
- ↑ 6.0 6.1 Sheppard, S. S.; and Jewitt, D. C.; An Abundant Population of Small Irregular Satellites Around Jupiter, Nature, Vol. 423 (May 2003), pp. 261-263
- ↑ 7.0 7.1 Grav, T.; Holman, M. J.; Gladman, B. J.; and Aksnes, K.; Photometric Survey of the Irregular Satellites, Icarus, Vol. 166 (2003), pp. 33-45
- ↑ Grav, T.; and Holman, M. J. (2004). "Near-Infrared Photometry of the Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal 605: pp. L141–L144. http://arxiv.org/abs/astro-ph/0312571.
Other websites [change]
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