90 Antiope
Adaptive-optics image of Antiope
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| Discovery [1] | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Discovered by | Robert Luther | ||||||||||||
| Discovery date | October 1, 1866 | ||||||||||||
| Designations | |||||||||||||
| 1952 BK2 | |||||||||||||
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Main belt (Themis family) |
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| Orbital characteristics | |||||||||||||
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Epoch July 23, 2010 (JD 2455400.5) |
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| Aphelion | 545.94 Gm 3.6494 AU |
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| Perihelion | 398.02 Gm 2.6606 AU |
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| 471.19 Gm 3.1550 AU |
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| Eccentricity | 0.15670 | ||||||||||||
| 2046.9 d (5.60 yr) | |||||||||||||
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Average orbital speed
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16.66 km/s | ||||||||||||
| 304.12° | |||||||||||||
| Inclination | 2.2195° | ||||||||||||
| 70.21° | |||||||||||||
| 242.96° | |||||||||||||
| Physical characteristics | |||||||||||||
| Dimensions | 93.0×87.0×83.6 km 87.8 ± 1.0 km |
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| Mass |
8.3×1017 kg |
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Mean density
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1.25 ± 0.05 g/cm³ (each) | ||||||||||||
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Equatorial surface gravity
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variable; ~ 0.03−0.04 m/s² | ||||||||||||
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Equatorial escape velocity
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variable; ~ 35−40 m/s | ||||||||||||
| 0.687 d (16.50 h) (synchronous) | |||||||||||||
| 0.060 | |||||||||||||
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| C | |||||||||||||
| 8.27 (together) 9.02 (each component) |
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| Discovery | |
|---|---|
| Discovered by |
W. J. Merline, L. M. Close, J. C. Shelton, C. Dumas, F. Menard, C. R. Chapman, and D. C. Slater |
| Discovery date | August 10, 2000 |
| Designations | |
| Main belt (Themis family) | |
| Orbital characteristics | |
| 171 ± 1 km | |
| Eccentricity | <0.006 |
| 0.687713 ± 0.00004 d (16.5051 ± 0.0001 h) | |
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Average orbital speed
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18.0 m/s |
| Satellite of | Binary with 90 Antiope |
| Physical characteristics | |
| Dimensions | 89.4×82.8×79.6 km 83.8 ± 1.0 km |
| Mass | ~ 8.1−8.5 ×1017 kg |
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Equatorial escape velocity
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variable; ~ 35−40 m/s |
| 0.687 d (16.50 h) (synchronous) | |
| 9.02 | |
8.3×1017 kg
(whole system)
90 Antiope (/ænˈtaɪ.əpiː/ an-TY-ə-pee) is a double asteroid in the outer asteroid belt. It was discovered on October 1, 1866, by Robert Luther. In 2000, it was found to consist of two almost-equally-sized bodies orbiting each other. At average diameters of about 88 km and 84 km, both components are among the 500 largest asteroids. Antiope is a member of the Themis family of asteroids that share similar orbital elements.
The number in 90 Antiope's name denotes that it was the 90th asteroid to be discovered. Its proper name comes from Greek mythology, but it is disputed whether this is Antiope the Amazon or Antiope the mother of Amphion and Zethus.
Since the discovery of Antiope's binary nature, the name "Antiope" technically refers to the slightly larger of the two components, with the smaller component bearing the provisional designation S/2000 (90) 1. However, the name "Antiope" is also used to refer to the binary system as a whole.
The most remarkable feature of Antiope is that it consists of two components of almost equal size (the difference in mass is less than 2.5%), making it a truly "double" asteroid. Its binary nature was discovered on 10 August 2000 by a group of astronomers using adaptive optics at the Keck Telescope on Mauna Kea. Before this, IRAS observations had suggested that the asteroid was 120 km in diameter.
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Wikipedia