Himalia (moon)

Himalia
Jupiter's moon Himalia, recorded by the Cassini-Huygens space probe on December 19, 2000 from a distance of 4.4 million kilometers
Central body	Jupiter
Properties of the orbit
Major semi-axis	11,461,000 km
Periapsis	9,601,000 km
Apoapsis	13,321,000 km
eccentricity	0.1623
Orbit inclination	27.496 °
Orbital time	250.56 d
Mean orbital velocity	3.30 km / s
Physical Properties
Albedo	0.04
Apparent brightness	14.62 mag
Medium diameter	170 km
Dimensions	6.7 × 10 18 kg
Medium density	2.6 g / cm 3
Sidereal rotation	7.782 h
Acceleration of gravity on the surface	0.062 m / s 2
Escape speed	≈ 102 m / s
discovery
Explorer	CD Perrine
Date of discovery	December 3, 1904

Himalia (also Jupiter VI) is the largest of the outer or irregular moons of the planet Jupiter .

discovery

Himalia was discovered on December 3, 1904 by the astronomer Charles Dillon Perrine at the Lick Observatory ( San José , California ).

The moon was named after the nymph Himalia , a lover of Zeus from Greek mythology . The official name was only given in 1975, before that Himalia was referred to as Jupiter's moon VI .

Orbit data

Himalia orbits Jupiter at a mean distance of 11,461,000 km in 250.56 days. The orbit has an eccentricity of about 0.16 and is inclined at 27.5 ° with respect to the local Laplace plane , which roughly coincides with the plane of the orbit of Jupiter.

Himalia is the namesake and at the same time the largest member of a group of moons that move on similar orbits around Jupiter. The moons Leda , Himalia, Lysithea and Elara belong to the Himalia group .

Physical data

Rotation light curve of Himalia from terrestrial observations between August and October 2010.

Earth-based observations calculated a mean diameter of 170 km for Himalia. Its density is relatively high at 2.6 g / cm³, which indicates that it is mainly composed of silicate rock. It has a very dark surface with an albedo of 0.04 to 0.06. The gray color indicates that Himalia may be a captured C-Type asteroid .

On December 19, 2000, the Cassini spacecraft sent images of the Himalia to Earth as it passed Jupiter on its way to Saturn . Since these were made from a great distance of 4.4 million kilometers, no details can be seen on their surface. Himalia can be seen in the pictures as a 4 to 6 pixel large object, which corresponds to about 27 km per pixel. From the angle of incidence of the sun, shape and slight divergences between the images, which were taken over a period of 4.5 hours, researchers from the German Aerospace Center conclude that Himalia is an irregular body with a diameter of approx. 150 km in one axis and 120 km is in the other axis.

It rotates around its own axis in 7 hours, 46 minutes and 55 ± 2 seconds.

Web links

• CD Perrine: "Discovery of a Sixth Satellite to Jupiter", in: Publications of the Astronomical Society of the Pacific , Vol. 17 (1905), No. 100, p. 22-23. (Discovery)
• "Discovery of a Sixth Satellite to Jupiter", in: Astronomical Journal , Vol. 24 (1905), Supplement to No. 570, p. 154B (discovery)
• Harvard College Observatory Bulletin , No. 173 (January 6, 1905) p. 1 (discovery)
• Harvard College Observatory Bulletin , No. 175 (January 25, 1905) p. 1 (discovery)
• CD Perrine: "Orbits of the Sixth and Seventh Satellites of Jupiter", in: Astronomische Nachrichten , Volume 169 (1905), Sp. 43-44.
• IAUC 2846: Satellites of Jupiter October 7, 1975 (designation)

Individual evidence

1. ↑ ^{a b c} Frederick Pilcher, Stefano Mottola, Tilmann Denk (2012): Photometric lightcurve and rotation period of Himalia (Jupiter VI). Icarus 219 , 741-742. doi : 10.1016 / j.icarus.2012.03.021
2. ↑ Archive link ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Jupiter's moon Himalia as a dissolved disk  

before	Jupiter moons	after that
Amalthea	Himalia	Elara