162173 Ryugu

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162173 Ryugu
Discovered by LINEAR
Discovery date 10 May 1999
MPC designation (162173) Ryugu
Named after
1999 JU3
NEO · PHA · Apollo[1]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 9567 days (26.19 yr)
Aphelion 1.4158 AU (211.80 Gm)
Perihelion 0.96328 AU (144.105 Gm)
1.1895 AU (177.95 Gm)
Eccentricity 0.19021
1.30 yr (473.88 d)
Inclination 5.8836°
Earth MOID 0.000320643 AU (47,967.5 km)
Physical characteristics
Dimensions 0.82 km (est at 0.057)[2]
0.980±29 km[3]
7.627 h (0.3178 d)[1]
SMASS = Cg[1]

162173 Ryugu, provisional designation 1999 JU3, is a dark asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, nearly one kilometer in diameter. It is the planned target of the Japanese space probe Hayabusa 2, a sample return mission launched in late 2014. The probe is scheduled to reach Ryugu in June 2018, and to return material from the asteroid to Earth by December 2020.

Ryugu has the rare spectral type Cg, with qualities of both a C-type asteroid and a G-type asteroid.



Ryugu was discovered in 1999 by the LINEAR project, and was given the provisional designation 1999 JU3.


The asteroid was officially named Ryugu on 5 October 2015,[4] its name refers to Ryūgū-jō (Dragon's Palace), a wonderful and magical palace on the bottom of the ocean where Urashima Tarō, in a Japanese folktale, was brought by a turtle. When he returned, he brought back with him a mysterious box—much as Hayabusa 2 will bring back a capsule with samples.


Planetary Resources speculates that the current value of the asteroid for mining purposes as of July 2016 is $95.02 billion.[5][not in citation given]

See also[edit]


  1. ^ a b c d "JPL Small-Body Database Browser: 162173 Ryugu (1999 JU3)". Jet Propulsion Laboratory. Retrieved 26 March 2016. 
  2. ^ "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 12 November 2017. 
  3. ^ Hasegawa, S.; et al. (2008). "Albedo, Size, and Surface Characteristics of Hayabusa-2 Sample-Return Target 162173 1999 JU3 from AKARI". Publications of the Astronomical Society of Japan. 60 (SP2): S399–S405. Bibcode:2008PASJ...60S.399A. doi:10.1093/pasj/60.sp2.s399. 
  4. ^ "Name Selection of Asteroid 1999 JU3 Target of the Asteroid Explorer "Hayabusa2"" (Press release). JAXA. October 5, 2015. Retrieved 2015-10-06. 
  5. ^ http://www.asterank.com/


External links[edit]