|Discovered by||S. B. Nicholson|
|Discovery time||September 28, 1951|
|Shortest distance from what it orbits around||12,567,000 km|
|Longest distance from what it orbits around||29,063,500 km|
|Avg. distance from the center of its orbital path||21,280,000 km|
|How egg-shaped its orbit is
|How long it takes to complete an orbit||610.45 d (1.680 a)|
|Average speed||2.367 km/s|
|Angle above the reference plane
|148.89° (to the ecliptic)
149.9° (to Jupiter's equator)
|What it orbits||Jupiter|
|Size and Other Qualities|
|Average distance from its center to its surface||14 km|
|Area of its surface||~2500 km²|
|Volume inside it||~11,500 km³|
|Average density||2.6 g/cm³ (assumed)|
|Gravity at its surface||0.010 m/s2 (0.001 g)|
|Slowest speed able to escape into space
|How much light it reflects||0.04 (assumed)|
|Avg. surface temp.||~124 K|
Ananke is a retrograde non-spherical moon of Jupiter. It was found by Seth Barnes Nicholson at Mount Wilson Observatory in 1951 and is named after the mythological Ananke, the mother of Adrastea by Jupiter. The adjectival form of the name is Anankean.
Ananke did not get its present name until 1975; before then, it was simply known as Jupiter XII. It was sometimes called "Adrastea" between 1955 and 1975. Note that Adrastea is now the name of another moon of Jupiter.
Orbit[change | edit source]
Ananke orbits Jupiter on a high eccentricity and high inclination retrograde orbit. Eight non-spherical moons found since 2000 follow similar orbits. The orbital elements are as of January 2000. They are changing a lot due to Solar and planetary perturbations. The diagram illustrates Ananke's orbit in relation to other retrograde non-spherical moons of Jupiter. The eccentricity of selected orbits is represented by the yellow segments (extending from the pericentre to the apocentre). The farthest spherical moon Callisto is located for reference.
Physical characteristics[change | edit source]
References[change | edit source]
- Jacobson, R. A. (2000). "The Orbits of Outer Jovian Satellites". Astronomical Journal 120: pp. 2679-2686. doi:10.1086/316817.
- Sheppard, S. S., Jewitt, D. C., Porco, C.; Jupiter's Outer Satellites and Trojans, in Jupiter: The Planet, Satellites and Magnetosphere, edited by Fran Bagenal, Timothy E. Dowling, William B. McKinnon, Cambridge Planetary Science, Vol. 1, Cambridge, UK: Cambridge University Press, ISBN 0-521-81808-7, 2004, pp. 263-280
- Nicholson, S. B. (1951). "An unidentified object near Jupiter, probably a new satellite". Publications of the Astronomical Society of the Pacific 63 (375): 297–299. http://adsabs.harvard.edu//full/seri/PASP./0063//0000297.000.html.
- Nicholson, S.B. (April 1939). "S. B. Nicholson declines to name the satellites of Jupiter he has discovered". Publications of the Astronomical Society of the Pacific 51 (300): 85–94. http://adsabs.harvard.edu//full/seri/PASP./0051//0000093.000.html.
- Marsden, B. G. (7 October 1974). "Satellites of Jupiter". IAUC Circular 2846. http://cfa-www.harvard.edu/iauc/02800/02846.html.
- Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-134-78107-4.
- Sheppard, S.S.; Jewitt, D.C. (2003). "An abundant population of small irregular satellites around Jupiter". Nature 423: 261-263.
- Nesvorný, D.; Beaugé, C.;Dones, L. (2004). "Collisional Origin of Families of Irregular Satellites". The Astronomical Journal 127: 1768–1783. http://www.journals.uchicago.edu/AJ/journal/issues/v127n3/203442/203442.html.
- Grav, Tommy (2003). "Photometric survey of the irregular satellites". Icarus 166: 33-45. doi:10.1016/j.icarus.2003.07.005.
- Grav, Tommy (2004). "Near-Infrared Photometry of the Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal 605: L141–L144. http://arxiv.org/abs/astro-ph/0312571.
- Ephemeris IAU-MPC NSES
Other websites[change | edit source]