+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   1802 Zhang Heng (1964 TW1) Classification: Main-belt Asteroid          SPK-ID: 2001802 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 38 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .03655317582487581 3.2049e-08   a 2.842308516224979 9.4983e-09 au q 2.738413113282865 9.1241e-08 au i 2.689719134876795 2.9007e-06 deg node 142.5645354588607 8.2716e-05 deg peri 296.2707345628892 9.5403e-05 deg M 156.7438058943863 4.8571e-05 deg tp 2458238.433030574026 (2018-Apr-29.93303057) 0.00023482 TDB period 1750.270815665936 4.79 8.7735e-06 2.402e-08 d yr n .2056824559821211 1.031e-09 deg/d Q 2.946203919167092 9.8455e-09 au   Orbit Determination Parameters    # obs. used (total)      3175      data-arc span      26006 days (71.20 yr)      first obs. used      1949-07-28      last obs. used      2020-10-09      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .42176      source      ORB      producer      Otto Matic      solution date      2020-Nov-13 04:15:19   Additional Information  Earth MOID = 1.75525 au   Jupiter MOID = 2.13518 au   T_jup = 3.306  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 11.7   n/a MPO347531   diameter diameter 13.333 km 0.110 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 3.162 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: [Simpson, G.; Chong, E.; Gerhardt, M.; Gorsky, S.; et al. (2013) Minor Planet Bull. 146-151.] [Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2015) Astron. J. 150, A75.] [Mannucci, M.; Montigiani, N. (2019) Minor Planet Bull. 46, 277-278.] geometric albedo albedo 0.228   0.026 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   1802 Zhang Heng (1964 TW1)          Discovered 1964-Oct-09 by Purple Mountain Observatory at Nanking Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  1964 TW1 = 1933 FH = 1936 YB = 1938 EB1 = 1948 JN = 1949 OV = 1955 YB = 1972 JX  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2020-Nov-29 08:35 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin