+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   944 Hidalgo (1920 HZ) Classification: Centaur          SPK-ID: 2000944 [ 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 31 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .6617809124726803 8.474e-08   a 5.737011459534766 5.8566e-08 AU q 1.940366780977625 4.7796e-07 AU i 42.54308634439113 2.1939e-05 deg node 21.56492602879133 1.4326e-05 deg peri 56.65082234879021 1.9627e-05 deg M 215.4034237231372 6.1471e-06 deg tp 2458416.462791611913 (2018-Oct-24.96279161) 0.00010815 JED period 5019.113340489356 13.74 7.6857e-05 2.104e-07 d yr n .07172581601133966 1.0983e-09 deg/d Q 9.533656138091906 9.7324e-08 AU   Orbit Determination Parameters    # obs. used (total)      628      data-arc span      32621 days (89.31 yr)      first obs. used      1920-10-31      last obs. used      2010-02-22      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-2      condition code      0      fit RMS      .59425      data source      ORB      producer      Otto Matic      solution date      2011-Sep-14 18:50:13   Additional Information  Earth MOID = 1.1433 AU   T_jup = 2.067  [ 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 10.77 mag n/a PDS3 (MPC 17260)   diameter diameter 38. km n/a Hazards due to Comets and Asteroids (1994), Ed. T. Gehrels, pp.540-543 based on assumed dark albedo (0.06) rotation period rot_per 10.063 h n/a Asteroid Lightcurve DataBase (Rev. 2013-May-01) Published Reference List: [Tedesco, E.F.; Drummond, J.D. (1976) IAUC 3007.] [Wisniewski, W.Z.; Michalowski, T.M.; Harris, A.W.; McMillan, R.S. (1997) Icarus 126, 395-449; 1995, Lunar & Planetary Science XXVI, 1511-1512.] [Wisniewski, W.Z.; Michalowski, T.M.; Harris, A.W.; McMillan, R.S. (1997) Icarus 126, 395-449; 1995, Lunar & Planetary Science XXVI, 1511-1512.] [Durech, J.; Kaasalainen, M.; Marciniak, A.; et al. (2007) Astron. Astrophys. 465, 331-337.] [Collaborative Asteroid Lightcurve Link (CALL) (2011) http://www.minorplanetobserver.com/DATA/submi ssions_results.htm] [Koff, R.A. (2011) http://www.antelopehillsobservatory.org] geometric albedo albedo 0.06   n/a DASTCOM value unverified B-V BV .743 mag .015 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=3; phase (min.=5.70, mean=13.30, max.=26.85) deg. U-B UB .260 mag .070 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=3; phase (min.=5.70, mean=13.30, max.=26.85) deg. Tholen spectral type spec_T D   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 2 color indices 944 Hidalgo (1920 HZ)          Discovered 1920-Oct-31 by Baade, W. at Bergedorf 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-19 01:24 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin