| Minorplanet: | yes |
| Background: |
|
| 299 Thora | |
| Discovered: | 6 October 1890 |
| Mpc Name: | (299) Thora |
| Alt Names: | A890 TA, 1935 PC 1939 PK |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Semimajor: | 2.43376AU |
| Perihelion: | 2.28265AU |
| Aphelion: | 2.58488AU |
| Eccentricity: | 0.062093 |
| Period: | 1386.8days |
| Inclination: | 1.60383° |
| Asc Node: | 241.531° |
| Arg Peri: | 150.672° |
| Rotation: | 274abbr=onNaNabbr=on |
| Abs Magnitude: | 11.3 |
| Mean Motion: | / day |
| Observation Arc: | 83.21 yr (30393 d) |
| Uncertainty: | 0 |
299 Thora is a 17 km Main belt asteroid with a potentially long 274-hour rotation period. It was discovered by Johann Palisa on 6 October 1890 in Vienna.
This object has a very low rate of spin, requiring 272.9± to complete a full rotation.