+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   140 Siwa (A874 TB) Classification: Main-belt Asteroid          SPK-ID: 2000140 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 152 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2141401020698535 3.4549e-08   a 2.734694957268412 7.7123e-09 au q 2.149087099989041 9.3362e-08 au i 3.185538900248087 3.6793e-06 deg node 107.1777306444042 5.9485e-05 deg peri 196.8153001044088 5.9973e-05 deg M 145.7487005347375 9.0961e-06 deg tp 2458331.749758012212 (2018-Aug-01.24975801) 4.0995e-05 TDB period 1651.816353986797 4.52 6.9876e-06 1.913e-08 d yr n .2179419032455453 9.2195e-10 deg/d Q 3.320302814547784 9.3638e-09 au   Orbit Determination Parameters    # obs. used (total)      3787      data-arc span      52464 days (143.64 yr)      first obs. used      1877-03-11      last obs. used      2020-10-31      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .4734      source      ORB      producer      Otto Matic      solution date      2020-Nov-13 04:32:57   Additional Information  Earth MOID = 1.13408 au   Jupiter MOID = 1.93021 au   T_jup = 3.317  [ 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 8.4   n/a MPO502154 IRAS observations used: 6 diameter diameter 109.79 km 3.0 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 6 rotation period rot_per 34.445 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List: [Pilcher, F. (2011) Minor Planet Bull. 38, 76-78.] [Pilcher, F. (2012) Minor Planet Bull. 39, 134-135.] geometric albedo albedo 0.0676   0.004 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 6 B-V BV 0.721   0.028 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=2; phase (min.=5.40, mean=9.53, max.=13.67) deg. U-B UB 0.299   0.025 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=2; phase (min.=5.40, mean=9.53, max.=13.67) deg. Tholen spectral type spec_T P   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 2 color indices; used ground-based radiometric albedo SMASSII spectral type spec_B Xc   n/a EAR-A-5-DDR-TAXONOMY-V4.0 based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002) 140 Siwa (A874 TB)          Discovered 1874-Oct-13 by Palisa, J. at Pola Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  A874 TB = 1948 AL  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2020-Dec-06 02:07 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin