Thebe (moon)

Thebe
Jupiter's moon Thebe with Zethus crater, recorded by the Galileo space probe on January 4, 2000
Provisional or systematic name	S / 1979 J 2
Central body	Jupiter
Properties of the orbit
Major semi-axis	221,900 km
Periapsis	218,000 km
Apoapsis	225,800 km
eccentricity	0.0176
Orbit inclination	1.080 °
Orbital time	0.675 d
Mean orbital velocity	23.90 km / s
Physical Properties
Albedo	0.047
Apparent brightness	16.0 mag
Medium diameter	99 km
Dimensions	1.51 x 10 18 kg
Medium density	approx. 1.00 g / cm 3
Sidereal rotation	0.675
Axis inclination	0.001 °
Acceleration of gravity on the surface	0.041 m / s 2
Escape speed	64 m / s
discovery
Explorer	Voyager 1
Date of discovery	March 5th 1979
Remarks	Simply bound rotation

Thebe (also Jupiter XIV) is one of the small inner moons of the planet Jupiter .

discovery

Thebe was discovered on March 5, 1979 by the astronomer Stephen P. Synnott on recordings of the space probe Voyager 1 and was initially given the provisional designation S / 1979 J 2 . Four months later, Voyager 2 was also observing the moon during a flyby. In 1983 it was officially named after the nymph Thebe , from Greek mythology , the daughter of the river god Asopos . At first little was known about Thebe, it was only between 1999 and 2002 that the Galileo probe made detailed images of almost the entire surface. Thebe is Jupiter's largest moon, which was only discovered using space probes; seven, in some cases significantly smaller, moons were discovered in the previous decades from Earth, by telescope or after looking through photo plates.

Track properties

Thebe is one of the regular moons of Jupiter; this means that it orbits it on an approximately circular orbit with little deviation from the plane of rotation of Jupiter and prograd , i.e. in its direction of rotation. Compared to the other regular moons, the eccentricity and the orbital inclination are again relatively high, which is explained by the gravitational influences of the large moon Io . Thebe belongs to the Amalthea group, which has its orbits very close to Jupiter and maintains its rings . Thebe feeds the so-called outer Gossamer ring, which extends between the orbits of the next inner moon Amalthea and from Thebe itself between 181,000 km and about 221,000 km. Thebes orbit is just outside the Roche limit .

Thebe shows a bound rotation , with its long axis always pointing towards Jupiter. One cycle takes a little more than 16 hours.

Structure and surface

Thebe is irregularly shaped and has dimensions of 116 × 98 × 84 km. It is the seventh largest moon of Jupiter after the Galilean moons , Amalthea and the largest irregular moon Himalia . Their surface is very dark and reddish in color with an albedo of 0.047. The space probe images show at least three huge impact craters , including the Zethus crater , which is about 40 km in diameter. Thebes density is unknown; Estimates are below that of water (1 g / cm³), similar to Amalthea.

gallery

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  Thebe on January 4, 2000 (Galileo)

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  Solar eclipses on Jupiter through Amalthea, Thebe, Io, Europa and Callisto on January 24th, 2015. The sun is shining from the lower left.

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  Scheme of the ring system of Jupiter; The Thebe-Gossamer-Ring is shown in green.

Web links

Commons : Thebe  - collection of images

• Jupiter's known satellites (English)
• IAUC 3470: Satellites of Jupiter April 28, 1980 (discovery)
• IAUC 3872: Satellites of Jupiter and Saturn September 30, 1983 (numbering and naming)
• Thebe in the Gazetteer of Planetary Nomenclature of the IAU (WGPSN) / USGS . Retrieved November 26, 2017

Individual evidence

1. ↑ Anderson et al .: Amalthea's density is less than that of water. Science. 2005 May 27; 308 (5726): 1291-3.

before	Jupiter moons	after that
Leda	Thebe	Adrastea