9549 Akplatonov

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9549 Akplatonov
Discovery [1]
Discovered by N. Chernykh
L. Chernykh
Discovery site Crimean Astrophysical Obs.
Discovery date 19 September 1985
MPC designation (9549) Akplatonov
Named after
Aleksandr Platonov
(computational mathematician)[2]
1985 SM2 · 1981 TU1
1987 BP3 · 1992 JK3
main-belt · Eunomia[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 35.58 yr (12,995 days)
Aphelion 2.8912 AU
Perihelion 2.3236 AU
2.6074 AU
Eccentricity 0.1089
4.21 yr (1,538 days)
0° 14m 2.76s / day
Inclination 11.153°
Physical characteristics
Dimensions 8.238±0.173 km[4][5]
9.17 km (calculated)[3]
2.8431±0.0004 h[6]
4.7045±0.0011 h[7]
0.21 (assumed)[3]
12.5[1][3] · 12.4[4] · 12.89±0.34[8] · 12.374±0.003 (R)[7]

9549 Akplatonov, provisional designation 1985 SM2, is a stony Eunomia asteroid from the middle region of the asteroid belt, approximately 9 kilometers in diameter.

It was discovered on 19 September 1985, by Soviet–Russian astronomer couple Nikolai and Lyudmila Chernykh at the Crimean Astrophysical Observatory, Nauchnyj, on the Crimean peninsula.[9] The asteroid was named for Russian computational mathematician Aleksandr Platonov.[2]

Orbit and classification[edit]

Akplatonov is a member of the Eunomia family, a large group of stony S-type asteroids and the most prominent family in the intermediate main-belt. It orbits the Sun in the central main-belt at a distance of 2.3–2.9 AU once every 4 years and 3 months (1,538 days). Its orbit has an eccentricity of 0.11 and an inclination of 11° with respect to the ecliptic.[1]

The body's observation arc begins 4 years prior to its official discovery observation, with its first identification as 1981 TU1 at the discovering observatory.[9]

Physical characteristics[edit]

Rotation period[edit]

According to the survey carried out by the NEOWISE mission of NASA's space-based Wide-field Infrared Survey Explorer, Akplatonov measures 8.2 kilometers in diameter and its surface has an albedo of 0.29,[4][5] while the Collaborative Asteroid Lightcurve Link (CALL) assumes an albedo of 0.21 – derived from 15 Eunomia, the family's largest member and namesake – and calculates a diameter of 9.17 kilometers with an absolute magnitude of 12.5.[3]

Diameter and albedo[edit]

A rotational lightcurve of Akplatonov was obtained from photometric observations using the 0.9-meter SARA telescope at Kitt Peak National Observatory in May 2009. It showed a rotation period of 2.8431 hours with a brightness variation of 0.15 magnitude (U=3-).[6] A second, fragmentary lightcurve from observations at the Palomar Transient Factory in August 2010, gave a period of 4.7 hours and has received a low quality rating by CALL (U=1).[7]


This minor planet was named in honor of Aleksandr Konstantinovich Platonov (born 1931), a Russian computational mathematician, roboticist, and astrodynamicist, long-time member at the Keldysh Institute of Applied Mathematics. He pioneered the research in walking robots, the computation of satellite orbits around Earth, and the guidance of the flight path of spacecrafts in the Solar System.[2] The official naming citation was published by the Minor Planet Center on 24 June 2002 (M.P.C. 46009).[10]


  1. ^ a b c d "JPL Small-Body Database Browser: 9549 Akplatonov (1985 SM2)" (2017-05-02 last obs.). Jet Propulsion Laboratory. Retrieved 22 June 2017. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (9549) Akplatonov. Springer Berlin Heidelberg. p. 698. ISBN 978-3-540-00238-3. Retrieved 4 May 2016. 
  3. ^ a b c d e f "LCDB Data for (9549) Akplatonov". Asteroid Lightcurve Database (LCDB). Retrieved 4 May 2016. 
  4. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 4 May 2016. 
  5. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096Freely accessible. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 4 December 2016. 
  6. ^ a b Murphy, Brian W.; Darragh, Andrew N.; Harp, Thomas W.; Liu, Zheyu J.; Geiss, Brian B.; Lawder, Matthew T.; et al. (July 2011). "Lightcurve Analysis of Asteroids (6577) 1978 VB6, 6619 Kolya, 9549 Akplatonov, (12466) 1997 AS12, (15154) 2000 FW30, and (32505) 2001 KF17". The Minor Planet Bulletin. 38 (3): 139–140. Bibcode:2011MPBu...38..139M. ISSN 1052-8091. Retrieved 4 May 2016. 
  7. ^ a b c Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041Freely accessible. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 4 May 2016. 
  8. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 4 May 2016. 
  9. ^ a b "9549 Akplatonov (1985 SM2)". Minor Planet Center. Retrieved 4 May 2016. 
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 4 May 2016. 

External links[edit]