Thorondor (moon)
| (385446) Manwë I (Thorondor) | |
|---|---|
| Provisional or systematic name | S / 2006 (385446) 1 |
| Central body | (385446) Manwë |
| Properties of the orbit | |
| Major semi-axis | 6,674 ± 41 km |
| Periapsis | 2,915 km |
| Apoapsis | 10,432 km |
| eccentricity | 0.5632 ± 0.0070 |
| Orbit inclination | 25.58 ± 0.23 ° |
| Orbital time | 110.176 ± 0.018 d |
| Physical Properties | |
| Medium diameter | 92 ± 14/26 km |
| Dimensions | 1.941 · 10 18 (system) kg |
| Medium density | 0.75 ± 0.25 (system) g / cm 3 |
| discovery | |
| Explorer |
|
| Date of discovery | July 25, 2006 |
| Remarks | Smaller component of a double asteroid system. |
Thorondor is the smaller component ( moon ) of the double asteroid system of the resonant Kuiper belt object (385446) Manwë (4: 7 resonance). Its mean diameter is an estimated 92 kilometers, which is about half the diameter of the mother asteroid .
Discovery and naming
Thorondor was discovered on July 25, 2006 by a team of astronomers consisting of Keith S. Noll, William M. Grundy, Denise C. Stephens, and Harold F. Levison in images from the Hubble Space Telescope on April 26, 2006. The discovery was published on September 7, 2006; the companion was given the provisional designation S / 2006 (2003 QW 111 ) 1 .
On April 15, 2014, the moon was officially named by the International Astronomical Union (IAU) after Thorondor, the leader of the Great Eagles in JRR Tolkien's Silmarillion . The name comes from the Elven language Sindarin and means "king of eagles".
Track properties
Orbit
Thorondor orbits Manwë at a distance of 6,674 km from its center (approx. 41.7 Manwë or 72.5 Thorondor radii). Since both revolve around the common center of gravity , the system is to be understood as a double asteroid system. Thorondor and Manwë circle each other in 110.17 days. This corresponds to 954.1 orbits in a Manwë year (around 287.8 earth years).
rotation
The observations of the light curves indicate that the rotation of Thorondor is chaotic, similar to that of Saturn's moon Hyperion .
Physical Properties
Thorondor is estimated to be 92 km in diameter (about 58% of the central body). However, the size determination is still very imprecise, the diameter is currently limited to between 66 and 106 km.
The size ratio of Manwë and Thorondor comes very close to the proportions of the Pluto - Charon system, which indicates that it is a double asteroid .
exploration
After its discovery, Thorondor and Manwë could be dated back to 2003 on photos and therefore the orbit of the system is now well known. Overall, the system has been observed by various telescopes such as the Hubble Space Telescope and also Earth-based telescopes, a total of 54 times within 10 years. (As of Oct. 2014)
Between July 16, 2014 and October 25, 2018, Thorondor and Manwë are going through a period of mutual occultations, which should enable an improved determination of radii and density, and possibly also the shapes and colors of the two bodies.