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162173 Ryugu (1999 JU3)
Classification: Apollo [NEO, PHA]          SPK-ID: 2162173
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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For accurate long-term ephemerides, please instead use our Horizons system.This orbit viewer was implemented using two-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances.

Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 233 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1909943708017178 1.2419e-08  
a 1.190568663805245 3.7034e-09 au
q .9631767509655204 1.573e-08 au
i 5.883716013376966 1.3237e-06 deg
node 251.5358517035736 1.0386e-05 deg
peri 211.4437103096276 1.257e-05 deg
M 345.6399295233192 6.4132e-06 deg
tp 2459219.427104015038
8.3887e-06 TDB
period 474.4933150905176
n .7587040503011595 3.5401e-09 deg/d
Q 1.41796057664497 4.4108e-09 au

Additional Model Parameters
 Parameter Value Uncertainty (1-sigma) 
A2 [EST] -2.160234004655858E-14 1.053E-14
ALN [SET] 1. n/a
NK [SET] 0. n/a
NM [SET] 2. n/a
R0 [SET] 1. n/a
  Orbit Determination Parameters
   # obs. used (total)      2042  
   data-arc span      12804 days (35.06 yr)  
   first obs. used      1986-04-14  
   last obs. used      2021-05-04  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .31552  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-May-08 05:51:08  

Additional Information
 Earth MOID = .000490989 au 
 Jupiter MOID = 3.69587 au 
 T_jup = 5.305 
 Nongravitational accels. using nonstandard g(r) = (1 au/ r)^2 
[ show covariance matrix ]

Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 19.39   n/a E2021B55  
rotation period rot_per 7.63262 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Result based on less than full coverage, so that the period may be wrong by 30 percent or so.
Published Reference List:
[Abe, M.; Kawakami, K.; Hasegawa, S.; Kuroda, D.; Yoshikawa, M.; et al. (2008) Lunar & Planetary Sci. XXXIX. No. 1391, p. 1594.]
[Muller, T.G.; Durech, J.; Hasegawa, S.; Abe, M.; et al. (2011) Astron. Astrophys. 525, A145.]
[Kim, M.-J.; Choi, Y.-J.; Moon, H.-K.; Ishiguro, M.; et al. (2013) Astron. Astrophys. 550, L11.]
[Moskovitz, N.A.; Abe, S.; Pan, K.-S.; Osip, D.J.; et al. (2013) Icarus 224, 24.]
[Muller, T.G.; Durech, J.; Ishiguro, M.; Mueller, M.; et al. (2017) Astron. Astrophys. 599, A103.]
[Watanabe, S.; Hirabayashi, M.; Hirata, N.; Hirata, Na.; et al. (2019) Science 364, 267-272.]
[Warner, B.D.; Stephens, R.D. (2021) Minor Planet Bull. 48-1, submitted. (NEA)]
SMASSII spectral type spec_B Cg   n/a Binzel et al. (2001) Icarus 151, 139-149  

162173 Ryugu           Discovered 1999 May 10 by the Lincoln Laboratory Near-Earth Asteroid Research Team at Socorro.
Ryugu is the undersea palace of the Dragon God. In a Japanese legend, a fisherman was rewarded with a visit to Ryugu and brought back a box with a secret. The spaceprobe Hayabusa 2 will visit this asteroid and bring back a capsule containing surface samples.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: MPC batch dated 2015-09-28Last Updated: 2015-10-05

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