Linus (moon)
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Discovery[1] and designation
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| Discovered by | Jean-Luc Margot and Michael E. Brown | |||||||||
| Discovery date | August 29, 2001 | |||||||||
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Designations
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| MPC designation | S/2001 (22) 1 | |||||||||
| Named after | Linus | |||||||||
| Minor planet category |
Main belt | |||||||||
| Adjective | Linian | |||||||||
| Semi-major axis | 1099 ± 11 km[2] | |||||||||
| Eccentricity | <0.005 [3] | |||||||||
| Orbital period | 3.590 ± 0.001 d[3] | |||||||||
| Average orbital speed | 21.5 m/s | |||||||||
| Inclination | ~0° [3] (undetectable with respect to Kalliope equator) |
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| Satellite of | 22 Kalliope | |||||||||
| Dimensions | 28 ± 2 km[2] | |||||||||
| Mass | ~4×1016 kg (estimate) | |||||||||
| Mean density | 3.4 g/cm3 (assumed) | |||||||||
| Equatorial escape velocity | ~20 m/s (estimate) | |||||||||
| Rotation period | unknown, probably synchronous[4] | |||||||||
| Axial tilt | unknown, zero expected | |||||||||
| Surface temp. Kelvin Celsius |
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| Absolute magnitude (H) | 9.7 [5] | |||||||||
(22) Kalliope I Linus is an asteroid moon that orbits the large M-type asteroid 22 Kalliope. It was discovered on August 29, 2001, by astronomers Jean-Luc Margot and Michael E. Brown with the Keck telescope. Another team also detected the moon with the Canada-France-Hawaii Telescope on September 2, 2001. Both telescopes are on Mauna Kea. It received the provisional designation S/2001 (22) 1, and was named on August 8, 2003, after the mythological Linus, son of the muse Calliope and the inventor of melody and rhythm.
With an estimated 28 ± 2 km diameter,[2] Linus is very large compared to most asteroid moons, and in fact would be a sizable asteroid by itself. The only known larger moons in the main belt are the smaller components of the double asteroids 617 Patroclus and 90 Antiope.
It has been estimated that Linus' orbit precesses at quite a rapid rate, making one cycle in several years. This is attributed primarily to the non-spherical shape of Kalliope.[5][6] Linus's brightness has varied appreciably between observations, which may indicate that its shape is elongated.[5]
Linus may have formed out of impact ejecta from a collision with Kalliope or a fragment captured after disruption of a parent asteroid (a proto-Kalliope).
[edit] References
- ^ IAUC 7703
- ^ a b c Descamps, P.; Marchis, F. et al (2008). "New determination of the size and bulk density of the binary asteroid 22 Kalliope from observations of mutual eclipses". Icarus 196 (2): 578–600. arXiv:0710.1471. Bibcode 2008Icar..196..578D. doi:10.1016/j.icarus.2008.03.014.
- ^ a b c synthesis of several observations including recent ones with the VLT 8m telescope.
- ^ Based on a rough tidal locking timescale of several tens of My.
- ^ a b c F. Marchis et al (2003). "A three-dimensional solution for the orbit of the asteroidal satellite of 22 Kalliope". Icarus 165 (1): 112. Bibcode 2003Icar..165..112M. doi:10.1016/S0019-1035(03)00195-7.
- ^ J.L. Margot & M.E. Brown (2003). "A Low-Density M-type Asteroid in the Main Belt". Science 300 (5627): 1939–42. Bibcode 2003Sci...300.1939M. doi:10.1126/science.1085844. PMID 12817147. http://www.sciencemag.org/cgi/content/full/300/5627/1939?ijkey=ikdx9/Weub/52&keytype=ref&siteid=sci.
[edit] External links
- IAUC 7703, announcing Linus' discovery
- IAUC 8177, announcing Linus' naming
- Link to the Linus discovery paper , "A Low-Density M-type Asteroid in the Main Belt"
- Kalliope and Linus very well resolved with the 8m VLT
- orbit diagram for Linus
- Information on Kalliope, Linus' orbit and several images
- A different VLT image of Kalliope and Linus
- another image of Kalliope and Linus
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