Petit-Prince (moon)

Petit-Prince, formal designation (45) Eugenia I, is the larger, outer moon of asteroid 45 Eugenia. It was discovered in 1998 by astronomers at the Canada-France-Hawaii Telescope on Mauna Kea, Hawaii. Initially, it received the provisional designation S/1998 (45) 1. Petit-Prince was the first asteroid moon to be discovered with a ground-based telescope. Previously, the only known moon of an asteroid was Dactyl, discovered by the Galileo space probe, around 243 Ida.

Petit-Prince

Discovery[1]
Discovered by	W. J. Merline, L. M. Close, C. Dumas, C. R. Chapman, F. Roddier, F. Menard, D. C. Slater, G. Duvert, J. C. Shelton, T. Morgan
Discovery date	1 November 1998
Designations
MPC designation	(45) Eugenia I
Pronunciation	/ˌpɛtiˈprɪns/ French: [pətipʁɛ̃s]
Named after	Napoléon, Prince Imperial and The Little Prince
Minor planet category	Main belt
Orbital characteristics[2]
Semi-major axis	1184 ± 12 km
Eccentricity	0.0100 ± 0.0002
Orbital period (sidereal)	4.766 ± 0.001 d
Average orbital speed	18.1 m/s
Inclination	7.0 ± 0.1° (with respect to Eugenia equator)
Satellite of	45 Eugenia
Physical characteristics
Dimensions	~ 13 km (estimate) [3]
Mass	~ 1.2×1015 kg (estimate) [4]
Equatorial escape velocity	~ 5 m/s (estimate)
Absolute magnitude (H)	13.6 [5]

Characteristics

Petit-Prince is 13 km in diameter, compared to 45 Eugenia's 214 km. It takes five days to complete an orbit around Eugenia.

Name

The discoverers chose the name in honour of Empress Eugénie's son, the Prince Imperial.^[6] However, they also intended an allusion to the children's book The Little Prince by Antoine de Saint-Exupéry, which is about a prince who lives on an asteroid.^[7]

In their submission of the name to the IAU, the discovers justified the double meaning by arguing for similarities between the Prince Imperial and the Little Prince:

"Both princes were young and adventurous, and had little fear of danger. Both were of rather small stature. They both left the confines of their cozy little worlds (asteroid B612 for the Little Prince and Chislehurst for the Prince Imperial). They both then undertook long journeys to end up in Africa, whereupon they both meet rather violent deaths ... And in both cases, they lay alone for one night each after "death" and then "returned" back home..."^[7]

See also

• 2578 Saint-Exupéry
• 46610 Bésixdouze, named B-six-twelve in French (and whose number equals the hexadecimal number B612)