Linus (moon)
| (22) Calliope I (Linus) | |
|---|---|
| Provisional or systematic name | S / 2001 (22) 1 |
| Central body | (22) Calliope |
| Properties of the orbit | |
| Major semi-axis | 1109 ± 6 km |
| Periapsis | 1091 ± 6 km |
| Apoapsis | 1127 ± 6 km |
| eccentricity | 0.016 ± 0.004 |
| Orbit inclination | (101 ± 1) or (9 ± 1) (equatorial plane) ° |
| Orbital time | 3.596 ± 0.001 d |
| Mean orbital velocity | 0.0215 km / s |
| Physical Properties | |
| Apparent brightness | 9.7 (absolute) mag |
| Medium diameter | 28 ± 2 km |
| Dimensions | (4 - 6 · 10 16 ) kg |
| Axis inclination | ~ 0.0 ° |
| Escape speed | (20) m / s |
| Surface temperature | (161) K. |
| discovery | |
| Explorer |
|
| Date of discovery | August 29, 2001 |
| Remarks | Second largest known asteroid moon in the main belt. |
Linus is a moon of the main belt asteroid (22) Calliope . With a diameter of 28 km, it is the second largest asteroid moon in the main belt.
Discovery and naming
Linus was discovered on August 29, 2001 by Jean-Luc Margot and Michael E. Brown at the Keck Observatory II . Just three days later, the team around William J. Merline, François Menard, Laird M. Close, Christophe Dumas, Clark R. Chapman and David C. Slater discovered him at the Canada-France-Hawaii Telescope . Both telescopes are on Mauna Kea in Hawaii . The discovery was announced by the International Astronomical Union (IAU) on September 3, 2001; the moon was given the provisional designation S / 2001 (22) 1 .
On August 8, 2003, Linus was officially named after Linos , who was considered the son of the muse Kalliope , grandson of Zeus and Mnemosyne and inventor of melody and rhythm in Greek mythology .
Linus ("the plaintiff") were the names of three different sons of Apollo , the most famous bearer of the name was the Gentile Christian Linus , named after them, who, according to church tradition, was the first successor of Simon Peter as Bishop of Rome.
Track properties
Linus orbits Calliope on a slightly retrograde , almost circular path between 1091 and 1127 km from its center (around 13 Calliope radii). The orbit eccentricity is 0.016% and the orbit is almost perpendicular to the equatorial plane of Calliope. This means that the moon moves well within the Kaliope Hill radius of 43,000 km.
Linus circles Calliope in around 3 1/2 days, which corresponds to almost 21 turns of Calliope.
The precession of the Linus orbit is estimated to be one revolution in just a few years, which is attributed to the irregular shape of Calliope. The brightness of the moon varied in different observations, which indicates an elongated shape.
Physical Properties
For some time, Linus was considered the largest asteroid moon in the main belt in absolute terms , as its diameter was initially estimated at 38 km and was subsequently corrected down by 10 km. Nevertheless, Linus is still comparatively large at 28 km, as it is only surpassed by S / 2002 (121) 1 (32 km), the moon of the asteroid (121) Hermione , and is therefore the second largest in the inner solar system. So far, only one natural satellite has been discovered in the main belt, which is even larger, the companion of the asteroid (90) Antiope (84 km). However, this system must be viewed as a double system, since S / 2000 (90) 1 has 95.4% of the diameter of Antiope and the barycentre is therefore outside the main body. In contrast, the size ratio relative to the central body is only 16.7% for Linus compared to Kalliope.
If one adds the Jupiter Trojans to the belt, then only the double system Patroclus / Menoetius would be added; Menoetius would be the largest moon in the inner solar system with 113 km, and Linus - including the Antiope system - would slide to fourth place.
Linus may have arisen from impact material from an impact on calliope or it is a fragment of a possible parent asteroid, a "proto-calliope". Like the mother body, Linus belongs to the metallic asteroids, so it is an M-type asteroid.
exploration
On November 7, 2006, the first star occultation by an asteroid moon was observed by a group of Japanese astronomers, based on a prognosis by the group around Franck Marchis, which is based on five years of observation of the Kalliope double system with adaptive optics by earth-based telescopes.
See also
Web links
Individual evidence
- ^ A b c Franck Marchis et al .: (22) Kalliope and Linus. Retrieved September 3, 2017 .
- ^ Daniel WE Green: IAUC No. 7703: S / 2001 (22) 1 Discovery Publication (2001). Retrieved September 3, 2017 .
- ^ Daniel WE Green: IAUC No. 8177: Satellites of (22) Kalliope and (45) Eugenia (designation 2003). Retrieved September 3, 2017 .
- ↑ Iraida Sokova: The binary asteroid 22 Kalliope: Linus orbit determination on the basis of speckle interferometric observations (2014). Retrieved September 2, 2017 .