+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   21383 (1998 EC9) Classification: Main-belt Asteroid          SPK-ID: 2021383 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 28 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .259346539899064 4.629e-08   a 2.548943070513237 1.0571e-08 au q 1.887883504775933 1.1793e-07 au i 6.313953175253054 4.7291e-06 deg node 86.25063154695124 3.1509e-05 deg peri 178.0908725634177 3.2184e-05 deg M 136.0496140838172 8.6095e-06 deg tp 2458638.762465195356 (2019-Jun-04.26246520) 3.3985e-05 TDB period 1486.410041597657 4.07 9.247e-06 2.532e-08 d yr n .2421942734005325 1.5067e-09 deg/d Q 3.210002636250541 1.3313e-08 au   Orbit Determination Parameters    # obs. used (total)      1226      data-arc span      10725 days (29.36 yr)      first obs. used      1991-10-02      last obs. used      2021-02-11      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .53152      source      ORB      producer      Otto Matic      solution date      2021-Apr-13 03:44:27   Additional Information  Earth MOID = .870401 au   Jupiter MOID = 1.88274 au   T_jup = 3.385  [ 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 14.4   n/a MPO435898   diameter diameter 3.079 km 0.334 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.355   0.187 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   21383 (1998 EC9)          Discovered 1998-Mar-02 by Beijing Schmidt CCD Asteroid Program at Xinglong Reference: 20010208/Numbers.arc Last Updated: 2004-04-19 [ show close-approach data ] Alternate Designations  1998 EC9 = 1999 RA180  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-16 12:49 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin