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22 Kalliope
From Wikipedia, the free encyclopedia
| Discovery | |
|---|---|
| Discovered by: | John Russell Hind |
| Discovery date: | November 16, 1852 |
| Alternative names: | none |
| Minor planet category: | Main belt |
| Orbital characteristics | |
| Epoch November 12, 2005 (JD 2453686.5) | |
| Aphelion distance: | 479.931 Gm (3.208 AU) |
| Perihelion distance: | 390.433 Gm (2.610 AU) |
| Semi-major axis: | 435.182 Gm (2.909 AU) |
| Eccentricity: | 0.103 |
| Orbital period: | 1812.245 d (4.96 a) |
| Avg. orbital speed: | 17.42 km/s |
| Mean anomaly: | 303.545° |
| Inclination: | 13.710° |
| Longitude of ascending node: | 66.240° |
| Argument of perihelion: | 356.172° |
| Physical characteristics | |
| Dimensions: | 215×180×150 km [1][2] |
| Mass: | 6.3 ± 0.5 ×1018 kg [3][4] |
| Mean density: | 2.03 ± 0.16 g/cm³ [3] |
| Equatorial surface gravity: | 0.038 m/s² |
| Escape velocity: | 0.09 km/s |
| Rotation period: | 0.1728 d (4.148 h) [5] |
| Albedo: | 0.142 [1] |
| Temperature: | ~161 K max: 240 K (-32°C) |
| Spectral type: | M [5] |
| Absolute magnitude: | 6.45 |
22 Kalliope (IPA: [kʰəˈlaɪʊpi]) is a large main belt asteroid of the M-type, discovered by J. R. Hind on November 16, 1852. It is named after Calliope, the Greek Muse of epic poetry.
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Kalliope is somewhat elongated, approximately 180 km in diameter, and slightly asymmetric, as evidenced by resolved images taken with the VLT at the European Southern Observatory [6].
While its spectrum is an M-type, Kalliope does not appear to be metallic, similarly to other M-types such as 21 Lutetia, for example. Firstly, its density, which is known with confidence from its satellite's orbit, is far too low to agree with any plausible metallic substance, even a rubble pile. It would have to be 70% porous, which is inconsistent with packing considerations. Furthermore, spectroscopic studies have shown evidence of hydrated minerals [7] and silicates [8], which indicate rather a stony surface composition. Kalliope also has a low radar albedo [4], which is again inconsistent with a metallic surface.
Lightcurve analysis indicates that Kalliope's pole most likely points towards ecliptic coordinates (β, λ) = (-23°, 20°) with a 10° uncertainty [2][3], which gives Kalliope an axial tilt of 103°. Kalliope's rotation is then slightly retrograde.
Kalliope has one known natural satellite, Linus. It is quite large being 30-40 km in diameter, and would be a sizeable asteroid by itself. It orbits about 1065 km from Kalliope, equivalent to about 12 Kalliope radii. Linus was discovered on August 29, 2001 by Jean-Luc Margot and Michael E. Brown, while another team also independently detected the moon 3 days later. [6]
- Kalliope and Linus very well resolved with the 8m VLT at ESO. Also includes a Kalliope shape model.
- shape model deduced from lightcurve
- orbit diagram for Linus
- A different VLT image of Kalliope and Linus
- Data sheet at Johnston's Archive, includes some other parameters.
- ^ a b Supplemental IRAS Minor Planet Survey
- ^ a b M. Kaasalainen et al (2002). "Models of Twenty Asteroids from Photometric Data". Icarus 159: 369.
- ^ a b c F. Marchis et al (2003). "A three-dimensional solution for the orbit of the asteroidal satellite of 22 Kalliope". Icarus 165: 112.
- ^ a b J.L. Margot & M.E. Brown (2003). "A Low-Density M-type Asteroid in the Main Belt". Science 300: 1939.
- ^ a b PDS lightcurve data
- ^ a b synthesis of several observations including recent ones with the VLT 8m telescope.
- ^ A.S. Rivkin et al (2000). "The nature of M-class asteroids from 3-micron observations". Icarus 145: 351.
- ^ D.F. Lupishko et al (1982). "UBV photometry of the M-type asteroids 16 Psyche and 22 Kalliope". Solar System Research 16: 75.
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| List of asteroids | ||
Vulcanoids · Near-Earth asteroids · Main belt · Jupiter Trojans · Centaurs · Damocloids · Comets · Trans-Neptunians (Kuiper belt • Scattered disc • Oort cloud)
For other objects and regions, see Asteroid groups and families, Binary asteroids, Asteroid moons and the Solar System.
For a complete listing, see List of asteroids. See also Pronunciation of asteroid names and Meanings of asteroid names.