 Kalliope and satellite Linus as seen by theW.M. Keck II telescope in 2010 | |||||||||||||
| Discovery[1] | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Discovered by | Jean-Luc Margot andMichael E. Brown | ||||||||||||
| Discovery date | August 29, 2001 | ||||||||||||
| Designations | |||||||||||||
| Kalliope I | |||||||||||||
| Pronunciation | /ˈlaɪnəs/ | ||||||||||||
Named after | Linus | ||||||||||||
| S/2001 (22) 1 | |||||||||||||
| Main belt | |||||||||||||
| Adjectives | Linian/ˈlɪniən/[2] | ||||||||||||
| Orbital characteristics | |||||||||||||
| 1063 ± 23km[3] (1040-1086) 1099 ± 11km[4] (1088-1110) | |||||||||||||
| Eccentricity | <0.015[3] <0.005[5] | ||||||||||||
| 3.596 ± 0.040d[3] (3.556-3.636) 3.590 ± 0.001d[5] (3.589-3.591) | |||||||||||||
Averageorbital speed | 21.5 m/s | ||||||||||||
| Inclination | ~0°[3][5] (undetectable with respect to Kalliope equator) | ||||||||||||
| Satellite of | 22 Kalliope | ||||||||||||
| Physical characteristics | |||||||||||||
| Dimensions | 28 ± 2 km[4] | ||||||||||||
| Mass | ~6×1016 kg(estimate)[3] ~4×1016 kg(estimate) | ||||||||||||
Meandensity | 3.4 g/cm3 (assumed) | ||||||||||||
Equatorialescape velocity | ~20 m/s(estimate) | ||||||||||||
| unknown, probablysynchronous[3][6] | |||||||||||||
| unknown, zero expected | |||||||||||||
| |||||||||||||
| 9.7[7] | |||||||||||||
Linus, formal designation(22) Kalliope I, is anasteroid moon that orbits the largeM-type asteroid22 Kalliope. It was discovered on August 29, 2001, byastronomersJean-Luc Margot andMichael E. Brown with theKeck telescope, inHawaii. Another team also detected the moon with theCanada-France-Hawaii Telescope on September 2, 2001. Both telescopes are onMauna Kea. It received theprovisional designation S/2001 (22) 1,[1] until it was named. The naming proposal appeared in the discovery paper[3] and was approved by theInternational Astronomical Union in July 2003.[8] Although the naming proposal referred to the mythologicalLinus, son of the museCalliope and the inventor of melody and rhythm, the name was also meant to honorLinus Torvalds, inventor of theLinux operating system kernel, andLinus van Pelt, a character in thePeanuts comic strip.[9]
With an estimated28 ± 2 km (17 ± 1 mi) diameter,[4] Linus is very large compared to most asteroid moons, and would be a sizable asteroid by itself. The only known larger moons in themain belt are the smaller components of the double asteroids617 Patroclus and90 Antiope.
It has been estimated that Linus' orbitprecesses at quite a rapid rate, making one cycle in several years. This is attributed primarily to the non-spherical shape of Kalliope.[3][7] Linus's brightness has varied appreciably between observations, which may indicate that its shape is elongated.[7]
Linus may have formed out ofimpactejecta from acollision with Kalliope, or a fragment captured after disruption of a parent asteroid (a proto-Kalliope).