| Minorplanet: | yes |
| Background: |
|
| 308 Polyxo | |
| Discovered: | 31 March 1891 |
| Mpc Name: | (308) Polyxo |
| Named After: | Πολυξώ Polyxō |
| Adjective: | Polyxoian |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Eccentricity: | 0.040003 |
| Inclination: | 4.36141° |
| Asc Node: | 181.727° |
| Arg Peri: | 115.501° |
| Mean Anomaly: | 70.4189° |
| Dimensions: | |
| Rotation: | 12.031± |
| Spectral Type: | T (Tholen) |
| Abs Magnitude: | 8.17 |
| Mean Motion: | / day |
| Uncertainty: | 0 |
308 Polyxo is a main-belt asteroid that was discovered by A. Borrelly on March 31, 1891, in Marseilles. It is orbiting the Sun at a distance of with a low orbital eccentricity (ovalness) of 0.04 and a period of . The orbital plane is tilted at an angle of 4.36° to the plane of the ecliptic.
308 Polyxo is classified as a rare T-type asteroid, with a spectrum that bears some similarity to the Tagish Lake meteorite. A spectral feature at a wavelength of suggests aqueous alteration of some surface materials. Photometric measurements reported in 1983 give a rotation period of 12.03 hours and a brightness variation of 0.20 in magnitude. The adaptive optics instrument at the W. M. Keck Observatory shows an oblate object with a diameter of 130 km. The size ratio between the major and minor axes is 1.26 ± 0.11. Light curves for this object suggests it has a very irregular shape.
Stellar occultation events were observed for this asteroid during 2000 and 2004. The resulting chords provided cross-section diameter estimates of 144.4 and 117.1 km, respectively.