Astronomy:308 Polyxo
 Orbital diagram | |
| Discovery | |
|---|---|
| Discovered by | A. Borrelly |
| Discovery date | 31 March 1891 |
| Designations | |
| (308) Polyxo | |
| Pronunciation | /pəˈlɪksoʊ/[1] |
| Named after | Πολυξώ Polyxō |
| Minor planet category | Main belt |
| Adjectives | Polyxoian /pɒlɪkˈsoʊiən/ |
| Orbital characteristics[2] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 124.63 yr (45,521 d) |
| |{{{apsis}}}|helion}} | 2.860 astronomical unit|AU (427.8 Gm) |
| |{{{apsis}}}|helion}} | 2.640 AU (394.9 Gm) |
| 2.750 AU (411.4 Gm) | |
| Eccentricity | 0.040003 |
| Orbital period | 4.56 yr (1,665.5 d) |
| Mean anomaly | 70.4189° |
| Mean motion | 0° 12m 58.158s / day |
| Inclination | 4.36141° |
| Longitude of ascending node | 181.727° |
| 115.501° | |
| Physical characteristics | |
| Dimensions | 140.69±3.8 km[2] 130 km[3] |
| Rotation period | 12.031 ± 0.009 h (0.50129 ± 0.00038 d)[4] |
| Geometric albedo | 0.043±0.002[5] |
| T[4] (Tholen) | |
| Absolute magnitude (H) | 8.17 |
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 astronomical unit|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.[2]
308 Polyxo is classified as a rare T-type asteroid, with a spectrum that bears some similarity to the Tagish Lake meteorite.[6] A spectral feature at a wavelength of 3.0 μm suggests aqueous alteration of some surface materials.[4] 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.[3] Light curves for this object suggests it has a very irregular shape.[4]
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.[7]
References
- ↑ Webster, Noah (1884), A Practical Dictionary of the English Language
- ↑ 2.0 2.1 2.2 "308 Polyxo". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=308;cad=1.
- ↑ 3.0 3.1 Marchis, F. et al. (November 2006), "Shape, size and multiplicity of main-belt asteroids. I. Keck Adaptive Optics survey", Icarus 185 (1): pp. 39–63, doi:10.1016/j.icarus.2006.06.001, PMID 19081813, Bibcode: 2006Icar..185...39M.
- ↑ 4.0 4.1 4.2 4.3 Dotto, E. et al. (December 2004), "308 Polyxo: ISO-SWS spectrum up to 26 micron", Astronomy and Astrophysics 427: 1081–1084, doi:10.1051/0004-6361:20041638, Bibcode: 2004A&A...427.1081D.
- ↑ Dotto, E. et al. (October 2002), "ISO observations of low and moderate albedo asteroids. PHT-P and PHT-S results", Astronomy and Astrophysics 393: 1065–1072, doi:10.1051/0004-6361:20021190, Bibcode: 2002A&A...393.1065D.
- ↑ Hiroi, Takahiro; Hasegawa, Sunao (March 2003), "Revisiting the search for the parent body of the Tagish Lake meteorite - Case of a T/D asteroid 308 Polyxo", Antarctic Meteorite Research 16: 176–184, Bibcode: 2003AMR....16..176H.
- ↑ Shevchenko, Vasilij G.; Tedesco, Edward F. (September 2006), "Asteroid albedos deduced from stellar occultations", Icarus 184 (1): 211–220, doi:10.1016/j.icarus.2006.04.006, Bibcode: 2006Icar..184..211S.
External links
- 308 Polyxo at AstDyS-2, Asteroids—Dynamic Site
- 308 Polyxo at the JPL Small-Body Database
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