Helike (moon)
| Helike | |
|---|---|
| Provisional or systematic name | S / 2003 J 6 |
| Central body | Jupiter |
| Properties of the orbit | |
| Major semi-axis | 21,263,000 km |
| Periapsis | 17,946,000 km |
| Apoapsis | 24,580,000 km |
| eccentricity | 0.156 |
| Orbit inclination | 154.8 ° |
| Orbital time | 634.8 d |
| Mean orbital velocity | 2.44 km / s |
| Physical Properties | |
| Albedo | 0.04 |
| Apparent brightness | 22.6 mag |
| Medium diameter | 4 km |
| Dimensions | 9.0 × 10 13 kg |
| Acceleration of gravity on the surface | ≈ 0 m / s 2 |
| Escape speed | ≈ 0 m / s |
| discovery | |
| Explorer | |
| Date of discovery | February 6, 2003 |
Helike (also Jupiter XLV) is one of the smaller moons of the planet Jupiter .
discovery
Helike was discovered by astronomers at the University of Hawaii on February 6, 2003 . It was initially given the provisional designation S / 2003 J 6 and was officially named after the ancient Greek city of Helike on March 30, 2005 by the International Astronomical Union (IAU) .
Orbit data
Helike orbits Jupiter at an average distance of 21,263,000 km in 634 days and 19 hours. The track has an eccentricity of 0.156. With an inclination of 154.8 ° from the local Laplace plane , the orbit is retrograde, i.e. that is, the moon moves around the planet against the direction of rotation of Jupiter.
Due to its orbital properties, Helike is assigned to the Ananke Group , named after the Jupiter moon Ananke .
Physical data
Helike has a diameter of about 4 km. Its density is estimated at 2.6 g / cm³. It is probably made up mainly of silicate rock. It has a very dark surface with an albedo of 0.04, i.e. that is, only 4% of the incident sunlight is reflected. Its apparent brightness is 22.6 m .
Web links
- IAUC 8087: Satellites of Jupiter March 4, 2003 (discovery)
- MPEC 2003-E11: S / 2003 J 1, 2003 J 2, 2003 J 3, 2003 J 4, 2003 J 5, 2003 J 6, 2003 J 7 March 4, 2003 (discovery)
- IAUC 8089: Satellites of Jupiter March 7, 2003 (partial revision of IAUC 8087)
- MPEC 2003-E29: S / 2003 J 9, 2003 J 10, 2003 J 11, 2003 J 12; S / 2003 J 1, 2003 J 6 March 7, 2003 (partial revision of MPEC 2003-E11)
- MPEC 2004-E30: S / 2003 J 6 March 10, 2004 (rediscovery)
- IAUC 8502: Satellites of Jupiter March 30, 2005 (numbering and naming)
| before | Jupiter moons | after that |
| Callichore | Helike |
Carpo |