+ 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 2459000.5 (2020-May-31.0) TDB Reference: JPL 26 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2259189600976912 3.3814e-08   a 2.399686376575064 8.8316e-09 au q 1.857551725818629 8.2243e-08 au i 1.17270209293726 3.6817e-06 deg node 262.64718284 0.00019927 deg peri 75.98254972189967 0.00019945 deg M 42.10868881232746 9.6116e-06 deg tp 2458841.682127667099 (2019-Dec-24.18212767) 3.5891e-05 TDB period 1357.782340235359 3.72 7.4956e-06 2.052e-08 d yr n .265138225275192 1.4637e-09 deg/d Q 2.941821027331498 1.0827e-08 au   Orbit Determination Parameters    # obs. used (total)      1728      data-arc span      16090 days (44.05 yr)      first obs. used      1975-12-01      last obs. used      2019-12-20      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .51951      source      ORB      producer      Otto Matic      solution date      2020-Feb-22 16:49:29   Additional Information  Earth MOID = .84901 au   Jupiter MOID = 2.45494 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 14.2   n/a MPO439098   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. 2019-August); 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 ] 2020-Aug-15 08:07 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin