4769 Castalia
|
|
| Discovery | |
|---|---|
| Discovered by |
E. F. Helin Palomar Observatory (675) |
| Discovery date | 9 August 1989 |
| Designations | |
| MPC designation | 4769 Castalia (1989 PB) |
|
Named after
|
Castalia |
|
Apollo NEO, PHA Venus-crosser asteroid, Mars-crosser asteroid |
|
| Orbital characteristics | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 9467 days (25.92 yr) |
| Aphelion | 1.5770 AU (235.92 Gm) (Q) |
| Perihelion | 0.54957 AU (82.215 Gm) (q) |
| 1.0633 AU (159.07 Gm) (a) | |
| Eccentricity | 0.48313 (e) |
| 1.10 yr (400.46 d) | |
| 327.23° (M) | |
| 0° 53m 56.256s / day (n) | |
| Inclination | 8.8863° (i) |
| 325.59° (Ω) | |
| 121.35° (ω) | |
| Known satellites | contact binary |
| Earth MOID | 0.0199597 AU (2.98593 Gm) |
| Jupiter MOID | 3.67272 AU (549.431 Gm) |
| Jupiter Tisserand parameter | 5.676 |
| Physical characteristics | |
| Dimensions | 1.4 km 1.8×0.8 km |
|
Mean radius
|
0.7 km |
| Mass | 5.0×1011 kg (?) |
|
Mean density
|
2.1 g/cm³ (?) |
| 4.095 h (0.1706 d) | |
|
Sidereal rotation period
|
4.095 h |
| Temperature | 216–366 K |
| S (?) | |
| 16.9 | |
The asteroid 4769 Castalia (/kəˈsteɪliə/ kə-STAY-lee-ə; previously known by the provisional designation 1989 PB) was the first asteroid to be modeled by radar imaging. It is an Apollo, Mars- and Venus-crosser asteroid. It was discovered on August 9, 1989, by Eleanor F. Helin (Caltech) on photographic plates taken at Palomar Observatory. It is named after Castalia, a nymph in Greek mythology.
On 25 August 1989 Castalia passed 0.0269378 AU (4,029,840 km; 2,504,020 mi) (within eleven lunar distances) of Earth, allowing it to be observed with radar from the Arecibo Observatory by Scott Hudson (Washington State University) and Steven J. Ostro (JPL). The data allowed Hudson et al. to produce a three-dimensional model of the object. During the 1989 passage Castalia peaked at an apparent magnitude of 12.
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