+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   498 Tokio (A902 XA) Classification: Main-belt Asteroid          SPK-ID: 2000498 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] 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  [ 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 8.91   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.DB Last Updated: 2003-08-29 Alternate Designations  A902 XA = A900 EB  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2021-Jun-15 02:04 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin