+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   11876 Doncarpenter (1990 EM1) Classification: Main-belt Asteroid          SPK-ID: 2011876 [ 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 33 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1556392069457727 3.4532e-08   a 2.430305658207968 7.3385e-09 au q 2.052054812928656 8.3816e-08 au i 5.405881490756371 3.5099e-06 deg node 234.09457980 3.874e-05 deg peri 92.55897956549323 4.0488e-05 deg M 254.1801690402368 1.3611e-05 deg tp 2459607.275077562785 (2022-Jan-27.77507756) 5.3198e-05 TDB period 1383.852408328684 3.79 6.268e-06 1.716e-08 d yr n .2601433489824119 1.1783e-09 deg/d Q 2.80855650348728 8.4806e-09 au   Orbit Determination Parameters    # obs. used (total)      1986      data-arc span      11258 days (30.82 yr)      first obs. used      1990-02-24      last obs. used      2020-12-21      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .47466      source      ORB      producer      Otto Matic      solution date      2021-Feb-24 02:02:54   Additional Information  Earth MOID = 1.04729 au   Jupiter MOID = 2.5302 au   T_jup = 3.485  [ 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 14.21   n/a E2021B10   11876 Doncarpenter           Discovered 1990 Mar. 2 by E. W. Elst at the European Southern Observatory. For the past 42 years, Don Carpenter (b. 1938) has been associated with the Stanford research group devoted to passive and active whistler-mode probing of the earth's ionosphere and magnetosphere. In 1966 he discovered the plasmapause in the electron-density distribution of the magnetosphere. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: 20010509/MPCPages.arc Last Updated: 2009-05-11 [ show close-approach data ] Alternate Designations  1990 EM1 = 1995 QR2  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Mar-08 14:02 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin