+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   3530 Hammel (1981 EC20) Classification: Main-belt Asteroid          SPK-ID: 2003530 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459396.5 (2021-Jul-01.0) TDB Reference: JPL 35 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2259914681269795 3.0518e-08   a 2.400406318732843 7.9211e-09 au q 1.857934970661129 7.3007e-08 au i 1.172341213243065 3.5697e-06 deg node 262.6402131235293 0.00016975 deg peri 76.06785639662463 0.00016994 deg M 146.9797073218375 9.8307e-06 deg tp 2458841.899257959525 (2019-Dec-24.39925796) 3.568e-05 TDB period 1358.393418877811 3.72 6.7238e-06 1.841e-08 d yr n .26501895179778 1.3118e-09 deg/d Q 2.942877666804556 9.7112e-09 au   Orbit Determination Parameters    # obs. used (total)      2038      data-arc span      16565 days (45.35 yr)      first obs. used      1975-12-01      last obs. used      2021-04-08      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .49831      source      ORB      producer      Otto Matic      solution date      2021-Jul-08 14:03:36   Additional Information  Earth MOID = .84862 au   Jupiter MOID = 2.45439 au   T_jup = 3.491  [ 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 14.23   n/a MPCxxxxx   diameter diameter 5.305 km 0.619 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   rotation period rot_per 4.53 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Result based on less than full coverage, so that the period may be wrong by 30 percent or so. Published Reference List: [Erasmus, N.; McNeill, A.; Mommert, N.; Trilling, D.E.; et al. (2019) Ap. J. Suppl. Series 242, A15.] geometric albedo albedo 0.173   0.059 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   3530 Hammel (1981 EC20)          Discovered 1981-Mar-02 by Bus, S. J. at Siding Spring Reference: DISCOVERY.DB Last Updated: 2003-08-29 Alternate Designations  1981 EC20 = 1975 XG1  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2021-Jul-29 07:00 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin