+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   2 Pallas Classification: Main-belt Asteroid          SPK-ID: 2000002 [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2455400.5 (2010-Jul-23.0) TDB Reference: JPL 25 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2309995596581508 1.9511e-08   a 2.772153211365543 1.7735e-09 AU q 2.131787040235174 5.4193e-08 AU i 34.84090359779853 2.1877e-06 deg node 173.1294969268293 3.6976e-06 deg peri 310.1509424754423 5.5397e-06 deg M 96.1482659817989 4.721e-06 deg tp 2454950.240146090154 (2009-Apr-28.74014609) 2.1989e-05 JED period 1685.87073050521 4.62 1.6178e-06 4.429e-09 d yr n .2135395042371473 2.0492e-10 deg/d Q 3.412519382495912 2.1832e-09 AU   Orbit Determination Parameters    # obs. used (total)      7575      data-arc span      67748 days (185.48 yr)      first obs. used      1825-03-23      last obs. used      2010-09-17      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-3P      condition code      0      fit RMS      .61113      data source      ORB      producer      Alan B. Chamberlin      solution date      2011-Feb-04 09:54:57   Additional Information  Earth MOID = 1.23163 AU   T_jup = 3.043  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 4.13 mag n/a IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 19 magnitude slope G 0.11   n/a PDS3 (MPC 17257) Fit diameter diameter 545 km 18 see ref. for extent computed from extent=582x556x500 km extent extent 582x556x500 km 18 Schmidt et al. 2008, LPSC XXXIX   GM GM 14.3 km^3/s^2 n/a JPL IOM 312.F01-006   rotation period rot_per 7.8132 h n/a Asteroid Lightcurve DataBase (Rev. 2013-May-01) Published Reference List: [Schroll, A.; Haupt, H.F.; Maitzen, H.M. (1976) Icarus 27, 147-156.] [Chang, Y.C.; Zhou, X.-h.; Yang, X.-y.; Zhang, Y.-y.; et al. (1981) Acta Astron. Sin. 22, 169-173; Chin. Astron. Astrophys. 5, 434-437.] [Magnusson, P. (1986) Icarus 68, 1-39.] [Lagerkvist, C.I.; Magnusson, P.; Williams, I.P.; Buontempo, M.E.; et al. (1988) Astron. Astrophys. Suppl. Ser. 73, 395-405.] [Torppa, J.; Kaasalainen, M.; Michalowski, T.; Kwiatkowski, T.; et al. (2003) Icarus 164, 346-383.] [Higley, S.; Hardersen, P.; Dyvig, R. (2008) Minor Planet Bul. 35, 63-66.] [Durech, J.; Kaasalainen, M.; Herald, D.; Dunham, D.; et al. (2011) Icarus 214, 652-670.] geometric albedo albedo 0.1587   0.013 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 19 B-V BV .635 mag .031 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=32; phase (min.=.19, mean=13.73, max.=25.65) deg. U-B UB .284 mag .018 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=14; phase (min.=7.23, mean=14.81, max.=25.65) deg. Tholen spectral type spec_T B   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo SMASSII spectral type spec_B B   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) 2 Pallas          Discovered 1802-Mar-28 by Olbers, H. W. at Bremen Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2013-May-22 17:47 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin