308 Polyxo
Polyxo (minor planet designation: 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 2.75 AU with a low orbital eccentricity (ovalness) of 0.04 and a period of 4.56 yr. The orbital plane is tilted at an angle of 4.36° to the plane of the ecliptic.
Orbital diagram | |
| Discovery | |
|---|---|
| Discovered by | A. Borrelly |
| Discovery date | 31 March 1891 |
| Designations | |
| (308) Polyxo | |
| Pronunciation | /pəˈlɪksoʊ/ |
Named after | Πολυξώ Polyxō |
| Main belt | |
| Adjectives | Polyxoian /pɒlɪkˈsoʊiən/ |
| Orbital characteristics | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 124.63 yr (45,521 d) |
| Aphelion | 2.860 AU (427.8 Gm) |
| Perihelion | 2.640 AU (394.9 Gm) |
| 2.750 AU (411.4 Gm) | |
| Eccentricity | 0.040003 |
| 4.56 yr (1,665.5 d) | |
| 70.4189° | |
| 0° 12m 58.158s / day | |
| Inclination | 4.36141° |
| 181.727° | |
| 115.501° | |
| Physical characteristics | |
| Dimensions | 140.69±3.8 km 130 km |
| 12.031 ± 0.009 h (0.50129 ± 0.00038 d) | |
| 0.043±0.002 | |
| T (Tholen) | |
| 8.17 | |
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 3.0 μm 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.