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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 ]

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For accurate long-term ephemerides, please instead use our Horizons system.This orbit viewer was implemented using two-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances.


Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 15 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .3497658344185369 3.9075e-08  
a 2.391783385643957 1.0325e-08 au
q 1.555219274015806 9.388e-08 au
i 4.285568844379206 4.7181e-06 deg
node 134.6097522392545 6.068e-05 deg
peri 193.370319144434 6.1234e-05 deg
M 212.1150675808712 1.3163e-05 deg
tp 2459755.512316017543
(2022-Jun-25.01231602)
5.2484e-05 TDB
period 1351.080400808101
3.70
8.7485e-06
2.395e-08
d
yr
n .2664534248181519 1.7253e-09 deg/d
Q 3.228347497272109 1.3936e-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 = .542265 au 
 Jupiter MOID = 2.14018 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 = 2.14018 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 15.85   n/a E2021B10  

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 2014-09-09Last Updated: 2014-11-10

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Alternate Designations
 1996 MR = 1995 FW6 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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