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498 Tokio (A902 XA)
Classification: Main-belt Asteroid          SPK-ID: 2000498
[ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

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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.


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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 77 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .222749433113143 3.3358e-08  
a 2.652218234654177 7.3848e-09 au
q 2.061438126392618 8.8267e-08 au
i 9.496873278462214 3.389e-06 deg
node 97.21168997304575 2.312e-05 deg
peri 241.7793974674468 2.4191e-05 deg
M 137.4817315219165 9.0025e-06 deg
tp 2458398.003117240252
(2018-Oct-06.50311724)		 3.8507e-05 TDB
period 1577.655993945149
4.32		 6.5892e-06
1.804e-08		 d
yr
n .2281866271111294 9.5304e-10 deg/d
Q 3.242998342915736 9.0297e-09 au
   Orbit Determination Parameters
   # obs. used (total)      4181  
   data-arc span      42412 days (116.12 yr)  
   first obs. used      1904-03-14  
   last obs. used      2020-04-26  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .38708  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-May-20 01:06:54  

Additional Information
 Earth MOID = 1.07172 au 
 Jupiter MOID = 2.1947 au 
 T_jup = 3.335 
[ show covariance matrix ]

[ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 8.9   n/a MPO502157 IRAS observations used: 15
diameter diameter 81.83 km 2.3 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 15
rotation period rot_per 41.85 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List:
[Pilcher, F.; Martinez, L. (2013) Minor Planet Bull. 40, 196-197.]
geometric albedo albedo 0.0694   0.004 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 15
B-V BV 0.780   0.024 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=4; phase (min.=.73, mean=10.06, max.=21.97) deg.
U-B UB 0.375   0.025 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=4; phase (min.=.73, mean=10.06, max.=21.97) deg.
Tholen spectral type spec_T M   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo

498 Tokio (A902 XA)          Discovered 1902-Dec-02 by Charlois, A. at Nice
Reference: DISCOVERY.DBLast Updated: 2003-08-29

Alternate Designations
 A902 XA = A900 EB 
[ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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