+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   24 Themis Classification: Main-belt Asteroid          SPK-ID: 2000024 [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2456400.5 (2013-Apr-18.0) TDB Reference: JPL 77 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1269372866747573 3.1526e-08   a 3.138425408343508 8.5057e-09 AU q 2.740042202577266 9.9709e-08 AU i .7524381185950528 3.4615e-06 deg node 35.97955068102713 0.00027486 deg peri 106.4708166495126 0.00027514 deg M 325.3047920457722 1.5181e-05 deg tp 2456596.219067403534 (2013-Oct-30.71906740) 8.6132e-05 JED period 2030.795271733958 5.56 8.2557e-06 2.26e-08 d yr n .1772704540978276 7.2065e-10 deg/d Q 3.53680861410975 9.5854e-09 AU   Orbit Determination Parameters    # obs. used (total)      2019      data-arc span      58353 days (159.76 yr)      first obs. used      1853-04-27      last obs. used      2013-01-31      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-2      condition code      0      fit RMS      .67839      data source      ORB      producer      Otto Matic      solution date      2013-Mar-29 14:40:25   Additional Information  Earth MOID = 1.75256 AU   T_jup = 3.199  [ 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 7.08 mag n/a PDS3 (MPC 17257)   magnitude slope G 0.19   n/a PDS3 (MPC 17257) Fit diameter diameter 198 km n/a J.G. Williams (E-mail September 1990) based on IRTF albedo of 0.067 rotation period rot_per 8.374 h n/a Asteroid Lightcurve DataBase (Rev. 2013-May-01) Published Reference List: [Tedesco, E.F. (1979) PhD Dissertation, New. Mex. State Univ. 280pp.] [Van Houten-Groeneveld, I.; van Houten, C.J.; Zappala, V. (1979) Astron. Astrophys. Suppl. Ser. 35, 223-232.] [Harris, A.W.; Young, J.W. (1983) Icarus 54, 59-109.] [Harris, A.W.; Young, J.W.; Bowell, E.; Martin, L.J.; et al. (1989) Icarus 77, 171-186.] [Chiorny, V.G.; Shevchenko, V.G.; Krugly, Yu.N.; Velichko, F.P.; Gaftonyuk, N.M. (2007) Planet. Space Sci. 55, 986-997.] [Ditteon, R.; Hawkins, S. (2007) Minor Planet Bul. 34, 59-64.] [Higley, S.; Hardersen, P.; Dyvig, R. (2008) Minor Planet Bul. 35, 63-66.] [Pilcher, F. (2012) http://aslc-nm.org/Pilcher.html] [Pilcher, F. (2013) Minor Planet Bul. 40, 85-87.] geometric albedo albedo 0.067   n/a J.G. Williams (E-mail September 1990) IRTF B-V BV .684 mag .030 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=10; phase (min.=.16, mean=9.29, max.=18.36) deg. U-B UB .336 mag .024 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=8; phase (min.=.16, mean=8.75, max.=18.36) deg. Tholen spectral type spec_T C   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) 24 Themis          Discovered 1853-Apr-05 by De Gasparis, A. at Naples Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  1947 BA = 1955 OH  [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2013-May-19 15:37 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin