+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   18499 Showalter (1996 MR) Classification: Mars-crossing Asteroid          SPK-ID: 2018499 [ 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 15 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .3496293720423047 3.9077e-08   a 2.392035138548831 1.0307e-08 au q 1.555709395154875 9.39e-08 au i 4.285264277977527 4.7179e-06 deg node 134.6089254384134 6.0681e-05 deg peri 193.3550010616751 6.1235e-05 deg M 158.8589916171913 1.2875e-05 deg tp 2458404.207893742820 (2018-Oct-12.70789374) 4.5134e-05 TDB period 1351.293723240241 3.70 8.7338e-06 2.391e-08 d yr n .266411361059802 1.7219e-09 deg/d Q 3.228360881942785 1.3911e-08 au   Orbit Determination Parameters    # obs. used (total)      647      data-arc span      9155 days (25.07 yr)      first obs. used      1995-03-01      last obs. used      2020-03-24      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .58158      source      ORB      producer      Otto Matic      solution date      2020-Nov-13 02:14:37   Additional Information  Earth MOID = .54469 au   Jupiter MOID = 2.13981 au   T_jup = 3.442  [ hide covariance matrix ] Orbital Elements at Epoch 2456772.5 (2014-Apr-25.0) TDB Reference: JPL 15 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .3511728558440428 3.9084e-08   q 1.550879795533056 9.3949e-08 au tp 2457053.508169475801 (2015-Jan-31.00816948) 3.8055e-05 TDB node 134.6877575165618 6.0626e-05 deg peri 193.3113093277073 6.1173e-05 deg i 4.288238751348259 4.7233e-06 deg   Orbit Determination Parameters    # obs. used (total)      647      data-arc span      9155 days (25.07 yr)      first obs. used      1995-03-01      last obs. used      2020-03-24      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .58158      source      ORB      producer      Otto Matic      solution date      2020-Nov-13 02:14:37   Additional Information  Jupiter MOID = 2.13981 au   T_jup = 3.442  Orbit Covariance (6×6)   e q tp node peri i e 1.527573677531879E-15 -3.662823288737427E-15 -1.753268197843045E-13 9.856321165387368E-15 -3.782031950677806E-14 7.668153600444365E-16 q -3.662823288737427E-15 8.826469782926223E-15 6.030591676943621E-13 -2.420224813768961E-14 1.256854584820316E-13 -1.536158024591289E-15 tp -1.753268197843045E-13 6.030591676943621E-13 1.448169868725736E-9 -2.278061141766006E-11 3.319399565629697E-10 2.277379564709999E-12 node 9.856321165387368E-15 -2.420224813768961E-14 -2.278061141766006E-11 3.675479848496102E-9 -3.669452306079658E-9 -1.883290296391898E-11 peri -3.782031950677806E-14 1.256854584820316E-13 3.319399565629697E-10 -3.669452306079658E-9 3.742132387889851E-9 1.923732451741747E-11 i 7.668153600444365E-16 -1.536158024591289E-15 2.277379564709999E-12 -1.883290296391898E-11 1.923732451741747E-11 2.230939392115185E-11 [ 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 15.8   n/a MPO452433   18499 Showalter           Discovered 1996 June 22 by NEAT at Haleakala. Mark R. Showalter (b. 1957), planetary scientist at the SETI Institute, is (co-)discover of the Jovian gossamer ring, Saturnian moon Pan, Uranian moons Mab and Cupid, two faint Uranian rings, Neptunian moon S/2004 N 1, and Plutonian moons Kerberos and Styx. He is the leader of the Planetary Data Systems Rings Node. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: MPC batch dated 2014-09-09 Last Updated: 2014-11-10 [ show close-approach data ] Alternate Designations  1996 MR = 1995 FW6  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Jan-22 08:10 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin