308 Polyxo
{{Short description|Main-belt asteroid}}
{{Use dmy dates|date=October 2024}}
{{Infobox planet
| minorplanet = yes
| background = #D6D6D6
| name = 308 Polyxo
| discoverer = Alphonse Borrelly
| discovered = 31 March 1891
| mpc_name = (308) Polyxo
|image= 308 Polyxo Orbit Diagram.png
|caption=Orbital diagram
| pronounced = {{IPAc-en|p|ə|'|l|ɪ|k|s|oʊ}}
| alt_names =
| named_after = Πολυξώ Polyxō
| adjective = Polyxoian {{IPAc-en|p|ɒ|l|ᵻ|k|'|s|oʊ|i|ə|n}}
| mp_category = Main belt
| epoch = 31 July 2016 (JD 2457600.5)
| semimajor = {{cvt|2.74975|AU|Gm|1|adj=ri3}}
| perihelion = {{cvt|2.63975|AU|Gm|1|adj=ri3}}
| aphelion = {{cvt|2.85974|AU|Gm|1|adj=ri3|lk=on}}
| eccentricity = 0.040003
| period = {{cvt|1665.5|days|years|2|order=flip}}
| inclination = 4.36141°
| asc_node = 181.727°
| arg_peri = 115.501°
| mean_anomaly = 70.4189°
| dimensions = {{val|140.69|3.8|ul=km}}
{{val|130|u=km}}
| mass =
| density =
| rotation = {{Convert|12.031|±|0.009|h|d|abbr=on|lk=on}}
| abs_magnitude = 8.17
| albedo = {{val|0.043|0.002}}
| mean_motion = {{Deg2DMS|0.216155|sup=ms}} / day
| observation_arc = {{cvt|45521|days|years|order=flip}}
| uncertainty = 0
}}
308 Polyxo is a main-belt asteroid that was discovered by Alphonse Borrelly on 31 March 1891, in Marseille. It is orbiting the Sun at a distance of {{val|2.75|ul=AU}} with a low orbital eccentricity (ovalness) of 0.04 and a period of {{cvt|1665.5|days|years|2|disp=out}}. 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 {{val|3.0|u=micrometre}} 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.
References
{{Reflist|refs=
| first=Noah | last=Webster | date=1884
| title=A Practical Dictionary of the English Language }}
| url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=308;cad=1
| title=308 Polyxo
| work=JPL Small-Body Database
| publisher=NASA/Jet Propulsion Laboratory
| access-date=11 May 2016 }}
| title=Revisiting the search for the parent body of the Tagish Lake meteorite - Case of a T/D asteroid 308 Polyxo
| last1=Hiroi | first1=Takahiro | last2=Hasegawa | first2=Sunao
| journal=Antarctic Meteorite Research | postscript=.
| volume=16 | pages=176–184 | date=March 2003
| bibcode=2003AMR....16..176H }}
| title=308 Polyxo: ISO-SWS spectrum up to 26 micron
| display-authors=1 | last1=Dotto | first1=E.
| last2=Barucci | first2=M. A. | last3=Brucato | first3=J. R.
| last4=Müller | first4=T. G. | last5=Carvano | first5=J.
| journal=Astronomy and Astrophysics | postscript=.
| volume=427 | pages=1081–1084 | date=December 2004
| doi=10.1051/0004-6361:20041638 | bibcode=2004A&A...427.1081D | doi-access=free }}
| title=ISO observations of low and moderate albedo asteroids. PHT-P and PHT-S results
| display-authors=1 | last1=Dotto | first1=E.
| last2=Barucci | first2=M. A. | last3=Müller | first3=T. G.
| last4=Brucato | first4=J. R. | last5=Fulchignoni | first5=M.
| last6=Mennella | first6=V. | last7=Colangeli | first7=L.
| journal=Astronomy and Astrophysics | postscript=.
| volume=393 | pages=1065–1072 | date=October 2002
| doi=10.1051/0004-6361:20021190 | bibcode=2002A&A...393.1065D | doi-access=free }}
| title=Shape, size and multiplicity of main-belt asteroids. I. Keck Adaptive Optics survey
| first1=F. | last1=Marchis | first2=M. | last2=Kaasalainen
| first3=E. F. Y. | last3=Hom | first4=J. | last4=Berthier
| first5=J. | last5=Enriquez | first6=D. | last6=Hestroffer
| first7=D. | last7=Le Mignant | first8=I. | last8=de Pater
| display-authors=1 | work=Icarus
| volume=185 | issue=1 | pages=39–63 | date=November 2006
| bibcode=2006Icar..185...39M | pmid=19081813
| doi=10.1016/j.icarus.2006.06.001 | pmc=2600456
| postscript=. }}
| title=Asteroid albedos deduced from stellar occultations
| last1=Shevchenko | first1=Vasilij G. | last2=Tedesco | first2=Edward F.
| journal=Icarus | postscript=.
| volume=184 | issue=1 | pages=211–220 | date=September 2006
| doi=10.1016/j.icarus.2006.04.006 | bibcode=2006Icar..184..211S }}
}}
External links
- {{AstDys|308}}
- {{JPL small body}}
{{Minor planets navigator |307 Nike |number=308 |309 Fraternitas}}
{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:Polyxo}}