Petit Prince (moon)
| (45) Eugenia I (Petit Prince) | |
|---|---|
| Provisional or systematic name | S / 1998 (45) 1 |
| Central body | (45) Eugenia |
| Properties of the orbit | |
| Major semi-axis | 1164.42 ± 0.03 km |
| Periapsis | 1162.09 km |
| Apoapsis | 1166.75 km |
| eccentricity | 0.0020 ± 0.0012 |
| Orbit inclination | 8.0 ° ± 0.1 ° |
| Orbital time | 4.7160 ± 0.0007 d |
| Mean orbital velocity | 0.0181 km / s |
| Physical Properties | |
| Albedo | 0.040 ± 0.002 |
| Medium diameter | 7.0 km |
| Dimensions | ≈ 1.2 · 10 15 kg |
| Medium density | ≈ 1.12 ± 0.3 g / cm 3 |
| Acceleration of gravity on the surface | ≈ 0 m / s 2 |
| Escape speed | ≈ 0 m / s |
| discovery | |
| Explorer |
|
| Date of discovery | November 1, 1998 |
| Remarks | Larger moon of the Eugenia system; second asteroid moon discovered |
Petit-Prince is the larger, outer moon of the main belt asteroid (45) Eugenia . It is the first asteroid moon to be discovered from Earth.
Discovery and naming
Petit-Prince was the second known asteroid moon after Dactyl on November 1, 1998 by a team of astronomers consisting of William J. Merline, Laird M. Close, Christophe Dumas, Clark R. Chapman, François Roddier, François Menard, David C. Slater, Gilles Duvert, J. Chris Shelton and Thomas Morgan discovered at the 3.6-meter Canada-France-Hawaii Telescope on Mauna Kea , Hawaii . It was the first asteroid moon to be discovered using earth-based telescopes. Dactyl, on the other hand, was accidentally detected by the Galileo probe flying past (243) Ida . The Petit-Prince discovery was announced on March 20, 1999; the moon was given the provisional designation S / 1998 (45) 1 .
The name of Petit-Prince gave the International Astronomical Union (IAU) the Moon on 3 October 2000. The explorers had Petit Prince proposed (no hyphen). On the one hand, they wanted to be the eldest (actually the only) son of the French Emperor Napoléon III. and his imperial wife Eugénie de Montijo, so titled Prince Imperial , Napoléon Eugène Louis Bonaparte . The Prince Imperial had died as a British officer in the Zulu War in 1879, a few years after his father's abdication and death . The name after the Prince Imperial was obvious because the mother body (45) discovered in 1857 Eugenia des Mondes was named after the mother Eugenie des Prince Imperial . On the other hand, the discoverers referred the name Petit Prince itself to the title of Antoine de Saint-Exupéry's book Le Petit Prince ( The Little Prince ), from which, in their opinion, many young people learn about asteroids for the first time. The "little prince" comes to earth from an asteroid that is supposedly called "B 612". At least Veronika was known when the book was published (612) . In 2002, an asteroid discovered in 1993 was named (46610) Bésixdouze , which could also be written as "B612". As a result, the asteroid "B 612" invented by Saint-Exupéry jokingly became a reality.
In 2007, the discovery of S / 2004 (45) 1 , which was found on images from 2004, allowed the Eugenia system to grow to the second known multiple asteroid system after (87) Sylvia . So far the system could only be observed through earth-based telescopes.
Track properties
Petit-Prince orbits Eugenia on a prograde , almost perfect circular path between 1,162 and 1,167 km from its center (major orbit half-axis 1164.42 km or 11.5 Eugenia radia). The orbit eccentricity is 0.002, the orbit is inclined 8 ° to the equator of Eugenia . With this, the moon moves well within Eugenia's Hill sphere of 37,000 km.
Petit-Prince's orbit is more circular and less inclined than that of its inner neighbor S / 2004 (45) 1, which is about 554 km away on average. Overall, the Eugenia system seems to be quite stable; it experiences slight interference from the sun and, to a lesser extent, from the mutual interactions between the moons. There is no evidence of orbital resonance , including the Kozai effect , which suggests that the inclinations of the moons' orbits were not caused by the influence of Eugenia.
Petit-Prince orbits Eugenia in 4 days, 18 hours and 23 minutes, which corresponds to about 343.78 orbits in one Eugenia year (around 4.5 earth years).
Physical Properties
Petit-Prince has an estimated diameter of 7 km (about 1/29 of the central body; according to other information, however, the moon could also be significantly larger at 12.7 ± 0.8 km), based on the assumed equal reflectivity of 4, which corresponds to Eugenia %. The surface is therefore extremely dark.
Assuming a mean diameter of 7 km, this results in an area of around 153 km 2 , which is just about the size of Liechtenstein .
Like Eugenia, the density is estimated at 1.12 g / cm 3 . It can therefore be assumed that Petit-Prince is porous on the inside and, like the mother body, belongs to the Rubble Piles . Another possibility would be a high occurrence of water ice , which, however, is rather unlikely due to the lack of water in Eugenia.
See also
Web links
- Wm. Robert Johnston: (45) Eugenia, Petit-Prince, and S / 2004 (45) 1 (English)
- William J. Merline: Astronomers Discover Moon Orbiting Asteroid (English)
Individual evidence
- ↑ Daniel WE Green: IAUC No. 7129: S / 1998 (45) 1 discovery publication (1999). Retrieved September 4, 2017 .
- ^ Daniel WE Green: IAUC No. 7503: S / 1998 (45) 1 designation (2000). Retrieved September 4, 2017 .
- ↑ October 3, 2000 (designation; English)
- ^ William J. Merline, Laird M. Close, Christophe Dumas, Clark R. Chapman, François Roddier, François Menard, David C. Slater, Gilles Duvert, J. Chris Shelton and Thomas Morgan: On a Permanent Name for Asteroid S / 1998 (45) 1. Southwest Research Institute Planetary Science Directorate, University of Colorado at Boulder , May 26, 2000 (proposed name).
- ↑ Yu Jiang et al .: Dynamical Configurations of Celestial Systems Comprised of Multiple Irregular Bodies (2016). Retrieved September 4, 2017 .
- ^ Franck Marchis et al .: A Dynamical Solution of the Triple Asteroid System (45) Eugenia (2010). Retrieved September 4, 2017 .