| Minorplanet: | yes |
| Background: |
|
| 646 Kastalia | |
| Mpc Name: | (646) Kastalia |
| Alt Names: | 1907 AC |
| Pronounced: | [1] |
| Discovered: | 11 September 1907 |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Eccentricity: | 0.21291 |
| Semimajor: | 2.325AU |
| Perihelion: | 1.83AU |
| Aphelion: | 2.82abbr=onNaNabbr=on |
| Period: | 3.55 yr (1294.9 d) |
| Inclination: | 6.9010° |
| Asc Node: | 302.820° |
| Arg Peri: | 38.142° |
| Mean Motion: | / day |
| Orbit Ref: | [2] |
| Observation Arc: | 108.60 yr (39665 d) |
| Uncertainty: | 0 |
| Abs Magnitude: | 12.6 |
646 Kastalia is a minor planet orbiting the Sun, not to be confused with the near-Earth asteroid 4769 Castalia.