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JPL Small-Body Database Browser
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18646 (1998 ED21)
Classification: Main-belt Asteroid          SPK-ID: 2018646
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

[ show orbit diagram ]
Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 26 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1065579271719354 3.4842e-08  
a 2.361832607312552 9.4423e-09 au
q 2.110160620350239 8.3656e-08 au
i 8.886715520375168 4.6514e-06 deg
node 157.3015783906544 2.3999e-05 deg
peri 295.9318016453231 3.4314e-05 deg
M 101.1609983631249 2.2324e-05 deg
tp 2458627.951598675986
(2019-May-24.45159868)
8.2289e-05 TDB
period 1325.781938165739
3.63
7.9505e-06
2.177e-08
d
yr
n .271537867304235 1.6284e-09 deg/d
Q 2.613504594274865 1.0448e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1220  
   data-arc span      12006 days (32.87 yr)  
   first obs. used      1987-02-23  
   last obs. used      2020-01-07  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .54767  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Jan-29 00:50:29  

Additional Information
 Earth MOID = 1.1439 au 
 Jupiter MOID = 2.53371 au 
 T_jup = 3.527 
[ hide covariance matrix ]
Orbital Elements at Epoch 2456730.5 (2014-Mar-14.0) TDB
Reference: JPL 26 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1058701307570267 3.4983e-08  
q 2.112526486653491 8.4003e-08 au
tp 2457302.718099828089
(2015-Oct-07.21809983)
8.3677e-05 TDB
node 157.3256846361814 2.3988e-05 deg
peri 296.1840293885264 3.4395e-05 deg
i 8.887020151177097 4.6522e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      1220  
   data-arc span      12006 days (32.87 yr)  
   first obs. used      1987-02-23  
   last obs. used      2020-01-07  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .54767  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Jan-29 00:50:29  

Additional Information
 Jupiter MOID = 2.53371 au 
 T_jup = 3.527 
Orbit Covariance (6×6)
  e q tp node peri i
e 1.223803094338411E-15 -2.923916731498811E-15 7.470277240609865E-13 -1.083970593717194E-14 2.371454554148455E-13 -9.865913322138956E-16
q -2.923916731498811E-15 7.056530122650956E-15 -1.870893383684842E-12 2.57010657362576E-14 -6.00109297464638E-13 2.571806472683208E-15
tp 7.470277240609865E-13 -1.870893383684842E-12 7.001889589782727E-9 -4.268401033616444E-11 2.071540882658914E-9 -4.06350466532646E-13
node -1.083970593717194E-14 2.57010657362576E-14 -4.268401033616444E-11 5.754416046456936E-10 -5.801341334482999E-10 1.702062725193536E-12
peri 2.371454554148455E-13 -6.00109297464638E-13 2.071540882658914E-9 -5.801341334482999E-10 1.183037962160025E-9 -1.79320695082196E-12
i -9.865913322138956E-16 2.571806472683208E-15 -4.06350466532646E-13 1.702062725193536E-12 -1.79320695082196E-12 2.164287676571606E-11

Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 14.8   n/a MPO467912  
diameter diameter 4.386 km 0.163 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
geometric albedo albedo 0.084   0.011 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

18646 (1998 ED21)          Discovered 1998-Mar-03 by Elst, E. W. at La Silla
Reference: 20001111/Numbers.arcLast Updated: 2004-04-19

Alternate Designations
 1998 ED21 = 1987 DD3 = 1996 RS2 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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