Open main menu

4647 Syuji, provisional designation 1931 TU1, is a dark background asteroid from the outer regions of the asteroid belt, approximately 14 kilometers (8.7 miles) in diameter. It was discovered on 9 October 1931, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany. The likely carbonaceous asteroid was named for Japanese astronomer Shuji Hayakawa.[1]

4647 Syuji
Discovery [1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date9 October 1931
MPC designation(4647) Syuji
Named after
Shuji Hayakawa[1]
(Japanese astronomer)
1931 TU1 · 1970 PD
1979 FN3 · 1979 GA
1980 RF4
main-belt[1][2] · (outer)
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc86.39 yr (31,553 d)
Aphelion3.6451 AU
Perihelion2.1369 AU
2.8910 AU
4.92 yr (1,795 d)
0° 12m 1.8s / day
Physical characteristics
Mean diameter
13.864±0.057 km[4]


Orbit and classificationEdit

Syuji is a non-family asteroid from the main belt's background population.[3] It orbits the Sun in the outer main-belt at a distance of 2.1–3.6 AU once every 4 years and 11 months (1,795 days; semi-major axis of 2.89 AU). Its orbit has an eccentricity of 0.26 and an inclination of 7° with respect to the ecliptic.[2] The body's observation arc begins at Heidelberg on 17 October 1931, or eight nights after its official discovery observation.[1]

Physical characteristicsEdit

Syuji has an absolute magnitude of 12.8.[2] Based on the body's albedo (see below) and its location in the asteroid belt, it is likely a carbonaceous asteroid. As of 2018, no rotational lightcurve of Syuji has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[2]

Diameter and albedoEdit

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Syuji measures 13.864 kilometers in diameter and its surface has an albedo of 0.063.[4]


This minor planet was named after Japanese astronomer Shuji Hayakawa (born 1958; first name also spelled "Syuji" or "Shūji"), an observer of comets and discoverer of minor planets at the Okutama Observatory (877) in Okutama, west of Tokyo.[1] The official naming was proposed by Takao Kobayashi and the citation was published by the Minor Planet Center on 25 May 1994 (M.P.C. 23540).[5]


  1. ^ a b c d e f "4647 Syuji (1931 TU1)". Minor Planet Center. Retrieved 17 May 2018.
  2. ^ a b c d e f "JPL Small-Body Database Browser: 4647 Syuji (1931 TU1)" (2018-02-27 last obs.). Jet Propulsion Laboratory. Retrieved 17 May 2018.
  3. ^ a b "Asteroid 4647 Syuji". Small Bodies Data Ferret. Retrieved 17 May 2018.
  4. ^ 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:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 17 May 2018.
  5. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 17 May 2018.

External linksEdit