Scamandrios (moon)
| Scamandrios | |
|---|---|
| Provisional or systematic name | S / 2006 (624) 1 |
| Central body | (624) Hector |
| Properties of the orbit | |
| Major semi-axis | 957.5 ± 55.3 km |
| Periapsis | 660.6 km |
| Apoapsis | 1254.3 km |
| eccentricity | 0.31 ± 0.03 |
| Orbit inclination | 45 ° |
| Orbital time | 2.965079 ± 0.000288 d |
| Physical Properties | |
| Medium diameter | 12 ± 3 km |
| Acceleration of gravity on the surface | ≈ 0 m / s 2 |
| Escape speed | ≈ 0 m / s |
| discovery | |
| Explorer |
|
| Date of discovery | July 16, 2006 |
| Remarks | First discovered and only L 4 Jupiter Trojan moon |
Skamandrios is a moon of the largest Jupiter Trojan (624) Hector , which precedes the planet in the Lagrange point L 4 . The mean diameter of the moon is around 12 kilometers, which is about a twentieth of the parent asteroid.
Discovery and naming
Skamandrios was discovered on July 16, 2006 by an astronomer team consisting of Franck Marchis, Michael H. Wong, Jérôme Berthier, Pascal Descamps, Daniel Hestroffer, Frédéric Vachier, D. Le Mignant and I. de Pater using adaptive optics with the 10-m - Keck Telescope II discovered on Mauna Kea in Hawaii . The moon is so far the only one of the four Trojan moons found so far that is comparatively small and therefore not part of a double system and therefore represents a "real" moon, in contrast to the system (617) Patroclus / Menoetius . Since the latter system, as well as the systems of (17365) 1978 VF 11 and (29314) Eurydama, are double systems, Hector's moon can also be regarded as the first discovered Trojan moon. So far it is the only known natural companion of the L 4 Trojans, the so-called «Greek group». The discovery was announced on July 21, 2006; the moon was given the provisional designation S / 2006 (624) 1 .
In March 2017, the moon was officially named after Skamandrios from Greek mythology . The hunter trained by Artemis fought on the side of Troy against the Achaeans in the Trojan War , but was killed in the first battle of Menelaus .
Since the discovery in 2006, Skamandrios and Hector have been observed several times by earth-based telescopes and Hector in 1993 by the Hubble space telescope , whereby the moon could not be found due to the insufficient resolution. In November 2011, observations with the Keck telescope confirmed the orbit data of the moon.
The records of Hector go back to his discovery in 1907; Light curve observations have been carried out at Hektor since 1957.
Track properties
S / 2006 (624) 1 orbits Hector in a very elliptical orbit at a mean distance of 957.5 kilometers (approx. 10.4 Hector or approx. 159.6 Skamandrios radii) to its center. The orbital eccentricity is 0.31 and the inclination about 45 °, which is rather unusual for an asteroid moon compared to the moons of the main belt . The moon's bizarre orbit and its stability due to Hector's elongated shape is not fully understood, but recent research has indicated that it is stable for millions of years.
Skamandrios orbits Hector in 2 days, 23 hours and 9.7 minutes, which corresponds to 1485.9 orbits in one Hector year (around 12.06 earth years). Conversely, it can be said that one cycle of skamandrios takes 10.283 hector days.
Physical Properties
It is possible that many of the Trojan asteroids are planetesimals that were captured during the outer migration of the giant planets in the Lagrangian points of the Jupiter - Sun system 3.9 billion years ago.
Hector has an elongated shape, but the exact shape is unclear. Initially, an ellipsoidal shape was assumed due to Hector's rapid rotation of almost 7 hours. More recent observations of the light curves indicated a club-shaped or dumbbell-shaped shape of the main body (cf. also (216) Cleopatra with her moons Cleoselene and Alexhelios ), which in turn indicates a merging of two original components; the moon could be a fragment of the comparatively slow collision of two icy asteroids that formed the Hector system. This theory is supported by the unusual orbit of Skamandrios.
The assumed density of the system is comparable to the Patroclus / Menoetius system, but given the differences in physical properties (Hektor is one of the D, Patroclus one of the P-type asteroids) and the reflected spectrum, both systems could have a different composition and Originate.
See also
Web links
- Wm. Robert Johnston: (624) Hektor and S / 2006 (624) 1 (English)
- Franck Marchis: Study with images of the Hektor system (2014, English)
- Franck Marchis: Another photo by (624) Hektor and S / 2006 (624) 1 (2011, English)