Themisto (moon) facts for kids
|Discovery date||November 21, 2000 rediscovered|
|Periapsis||5,909,000 km (0.039 AU)|
|Apoapsis||8,874,300 km (0.059 AU)|
Mean orbit radius
|7,391,650 km (0.04941 AU)|
|129.82761 d (0.3554 a)|
Average orbital speed
|Inclination||45.81° (to the ecliptic)
47.48° (to Jupiter's equator)
|2.6 g/cm3 assumed|
|~0.0029 m/s2 (0.0003 g)|
Discovery and naming
Themisto was first found by Charles T. Kowal and Elizabeth Roemer on September 30, 1975, reported on October 3, 1975 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. Then, in 2000, a seemingly new moon was found 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 1975 object. The Sheppard et al. announcement was immediately correlated with an August 6 2000 observation 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 — an observation that was reported to the Minor Planet Center but not published as an IAU Circular (IAUC).
Themisto is about 8 kilometers in diameter (assuming an albedo of 0.04)
Images for kids
Themisto (moon) Facts for Kids. Kiddle Encyclopedia.