4769 Castalia
|
|
| Missing image Asteroid_4769_Castalia.faces_model.jpg A 3D model of the different faces of Castalia. Image by AAAS. | |
| Orbital characteristics | |
|---|---|
| Orbit type | Near-Earth, Venus-crosser asteroid, Mars-crosser asteroid |
| Semimajor axis | 1.063 AU |
| Eccentricity | 0.4831 |
| Orbital period | 1.10 year |
| Inclination | 8.89° |
| Physical characteristics | |
| Diameter | 1.8×0.8 km |
| Mass | 5.0×1011 kg |
| Density | 2.1 g/cm3 |
| Rotation period | 4 h |
| Spectral class | S |
| Albedo | ? |
| History | |
| Discoverer | E. F. Helin, August 9, 1989 |
The asteroid 4769 Castalia (previously known by the provisional designation 1989 PB) was the first asteroid to be directly imaged. 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.
General information
Castalia's orbit took it within 11 lunar distances of Earth, allowing it to be scanned with radar from the Arecibo Observatory by Scott Hudson (Washington State University) and Steven J. Ostro (JPL). The obtained data allowed astronomers to produce a three-dimensional computer model of it.
Castalia was found to have a peanut shape, suggesting two 800 m diameter pieces held together by their weak mutual gravity. Since then radar measurements of other asteroids has indicated that this contact binary arrangement appears to be common.
Related topics
External links
- NASA Asteroid Radar Search - The 228 Radar-Detected Asteroids: Asteroid 4769 Castalia (http://echo.jpl.nasa.gov/asteroids/4769_Castalia/cast01.html)
- Scott Hudson's Homepage: Castalia (http://www.eecs.wsu.edu/~hudson/Castalia/castalia.html)
| The minor planets |
| Vulcanoids | Main belt | Groups and families | Near-Earth objects | Jupiter Trojans |
| Centaurs | Trans-Neptunians | Damocloids | Comets | Kuiper belt | Oort cloud |
| (For other objects and regions, see: Binary asteroids, Asteroid moons and the Solar system) |
| (For a complete listing, see: List of asteroids. For pronunciation, see: Pronunciation of asteroid names.) |