+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   18239 Ekers (1251 T-2) Classification: Main-belt Asteroid          SPK-ID: 2018239 [ 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 .1565383187737286 3.7015e-08   a 3.089304644620354 1.598e-08 au q 2.605710089371613 1.1117e-07 au i 1.245833871464042 4.338e-06 deg node 152.0198878826426 0.00023023 deg peri 311.9354166436422 0.00023087 deg M 186.680231529056 1.7765e-05 deg tp 2460155.349955843829 (2023-Jul-29.84995584) 0.00010172 TDB period 1983.305119412303 5.43 1.5388e-05 4.213e-08 d yr n .1815151871874742 1.4083e-09 deg/d Q 3.572899199869096 1.8481e-08 au   Orbit Determination Parameters    # obs. used (total)      1637      data-arc span      17125 days (46.89 yr)      first obs. used      1973-09-19      last obs. used      2020-08-08      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .53563      source      ORB      producer      Otto Matic      solution date      2021-Apr-13 02:25:35   Additional Information  Earth MOID = 1.62263 au   Jupiter MOID = 1.57293 au   T_jup = 3.206  [ 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 13.56   n/a E2021B10   diameter diameter 10.257 km 0.481 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.061   0.011 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   18239 Ekers           Discovered 1973 Sept. 29 by C. J. van Houten and I. van Houten-Groeneveld on Palomar Schmidt plates taken by T. Gehrels. Ronald Ekers, current president of the IAU and ex-director of the Australian Telescope National Facility and of the Very Large Array, is well known for his contributions to radio astronomy and his innovative exploitation of radio techniques to study galaxies. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: 20031110/MPCPages.arc Last Updated: 2003-11-12 [ show close-approach data ] Alternate Designations  1251 T-2 = 1981 EU  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-19 19:59 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin