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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.


Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 85 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2229031449924569 2.2228e-08  
a 2.651965112932881 6.0323e-09 au
q 2.060833748849865 5.7606e-08 au
i 9.496432659983547 5.8533e-07 deg
node 97.20851077699457 2.8883e-06 deg
peri 241.8007598543181 3.2995e-06 deg
M 183.0888591081504 3.4989e-06 deg
tp 2459975.680464059696
(2023-Jan-31.18046406)
1.7338e-05 TDB
period 1577.430147443853
4.32
5.3821e-06
1.474e-08
d
yr
n .2282192974334629 7.7868e-10 deg/d
Q 3.243096477015896 7.3769e-09 au
  Orbit Determination Parameters
   # obs. used (total)      4596  
   data-arc span      42744 days (117.03 yr)  
   first obs. used      1904-03-14  
   last obs. used      2021-03-24  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .37985  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-May-03 18:29:11  

Additional Information
 Earth MOID = 1.0693 au 
 Jupiter MOID = 2.19499 au 
 T_jup = 3.335 
[ hide covariance matrix ]
Orbital Elements at Epoch 2456740.5 (2014-Mar-24.0) TDB
Reference: JPL 85 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2249080660800693 2.2489e-08  
q 2.054454373830954 5.8504e-08 au
tp 2456817.800540442335
(2014-Jun-09.30054044)
1.0969e-05 TDB
node 97.44604084617603 2.8875e-06 deg
peri 241.0108502562183 3.2723e-06 deg
i 9.501113505281957 5.8611e-07 deg
  Orbit Determination Parameters
   # obs. used (total)      4596  
   data-arc span      42744 days (117.03 yr)  
   first obs. used      1904-03-14  
   last obs. used      2021-03-24  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .37985  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-May-03 18:29:11  

Additional Information
 Jupiter MOID = 2.19499 au 
 T_jup = 3.335 
Orbit Covariance (6×6)
  e q tp node peri i
e 5.057414480446331E-16 -1.31197180451605E-15 1.129669410444899E-13 -6.120430938490881E-15 -3.362760222872452E-15 -3.834940965823507E-15
q -1.31197180451605E-15 3.422735914634642E-15 -2.860336650154714E-13 1.544754993987677E-14 1.1352737249365E-14 9.86827966056139E-15
tp 1.129669410444899E-13 -2.860336650154714E-13 1.203094405335529E-10 5.313107539425499E-13 1.724751388200421E-11 -2.636534509933712E-12
node -6.120430938490881E-15 1.544754993987677E-14 5.313107539425499E-13 8.337462890371302E-12 -7.093412619056637E-12 7.002524453366626E-13
peri -3.362760222872452E-15 1.1352737249365E-14 1.724751388200421E-11 -7.093412619056637E-12 1.070763534865581E-11 -9.122585193583792E-13
i -3.834940965823507E-15 9.86827966056139E-15 -2.636534509933712E-12 7.002524453366626E-13 -9.122585193583792E-13 3.43528185071262E-13

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

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 8.91   n/a MPCxxxxx 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. 2020-October); Warner et al., 2009 Published Reference List:
[Pilcher, F.; Martinez, L. (2013) Minor Planet Bull. 40, 196-197.]
[Pal, A.; Szakats, R.; Kiss, C.; Bodi, A.; et al. (2019) Ap. J. Supl. Ser. 247, id.26.]
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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