| Discovery [1] | |
|---|---|
| Discovered by | N. Chernykh L. Chernykh |
| Discovery site | Crimean Astrophysical Obs. |
| Discovery date | 19 September 1985 |
| Designations | |
| (9549) Akplatonov | |
Named after | Aleksandr Platonov [2] (computational mathematician) |
| 1985 SM2 · 1981 TU1 1987 BP3 · 1992 JK3 | |
| main-belt [1][3] · (middle) background [4] · Eunomia [5][6] | |
| Orbital characteristics [3] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 37.03yr (13,526 d) |
| Aphelion | 2.8896AU |
| Perihelion | 2.3237 AU |
| 2.6067 AU | |
| Eccentricity | 0.1086 |
| 4.21 yr (1,537 d) | |
| 183.99° | |
| 0° 14m 3.12s / day | |
| Inclination | 11.154° |
| 235.19° | |
| 305.61° | |
| Physical characteristics | |
| 8.238±0.173 km[7][8][9] | |
| 2.8431±0.0004 h[10] | |
| 0.285[7][8][9] | |
| S(assumed)[6] | |
| 12.40[7][9] 12.5[1][3][6] | |
9549 Akplatonov, provisional designation1985 SM2, is anEunomia asteroid from the central region of theasteroid belt, approximately 8.2 kilometers (5.1 miles) in diameter. It was discovered on 19 September 1985, by Soviet–Russian astronomer coupleNikolai andLyudmila Chernykh at theCrimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula.[1] The likelyS-type asteroid has a relatively shortrotation period of 2.8 hours.[6] It was named for Russian computational mathematicianAleksandr Platonov.[2]
Akplatonov is a core member of theEunomia family,[5] a large group of stonyS-type asteroids and the most prominent family in the intermediate main-belt. Alternatively, in Nesvorný'sHCM-analysis, the asteroid belong's to the main belt'sbackground population, while in an earlier such analysis, Thais Mothé-Diniz consideredAkplatonov to be the largest body in a smallcluster orclump of its own.[4] It orbits the Sun in thecentral asteroid belt at a distance of 2.3–2.9 AU once every 4 years and 3 months (1,537 days;semi-major axis of 2.61 AU). Its orbit has aneccentricity of 0.11 and aninclination of 11° with respect to theecliptic.[3] The body'sobservation arc begins 4 years prior to its official discovery observation, with its first identification as1981 TU1 at the discovering observatory in October 1981.[1]
Thisminor planet was named in honor ofAleksandr Konstantinovich Platonov (born 1931), a Russian computational mathematician,roboticist,astrodynamicist, and long-time member at theKeldysh Institute of Applied Mathematics. He pioneered the research inwalking robots, the computation of satellite orbits around Earth, and the guidance of the flight path of spacecraft in the Solar System.[2] The officialnaming citation was published by theMinor Planet Center on 24 June 2002 (M.P.C. 46009).[11]
A rotationallightcurve ofAkplatonov was obtained from photometric observations using the 0.9-meter SARA telescope atKitt Peak National Observatory in May 2009. It showed arotation period of2.8431±0.0004 hours with a brightness variation of 0.15magnitude (U=3-).[10] A poorly rated period determination from a fragmentary lightcurve by astronomers at thePalomar Transient Factory in 2010 gave a period of 4.7 hours (U=1).[12]
According to the survey carried out by theNEOWISE mission of NASA's space-basedWide-field Infrared Survey Explorer,Akplatonov measures 8.2 kilometers in diameter and its surface has analbedo of 0.285,[7][8][9] while theCollaborative Asteroid Lightcurve Link (CALL) assumes an albedo of 0.21 – derived from15 Eunomia, the family's largest member and namesake – and calculates a diameter of 9.17 kilometers using anabsolute magnitude of 12.5.[6]
