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21085 (1991 UL4)
Classification: Main-belt Asteroid          SPK-ID: 2021085
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

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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 2459396.5 (2021-Jul-01.0) TDB
Reference: JPL 28 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2246571569498013 3.9947e-08  
a 2.674918857586237 1.1635e-08 au
q 2.073979191969503 1.1135e-07 au
i 4.8847329833395 3.5619e-06 deg
node 75.55946419750563 4.7499e-05 deg
peri 316.5071020654253 4.8199e-05 deg
M 285.9512261053658 9.5537e-06 deg
tp 2459725.184872622917
(2022-May-25.68487262)
4.3866e-05 TDB
period 1597.954266097909
4.37
1.0426e-05
2.854e-08
d
yr
n .2252880496255343 1.4698e-09 deg/d
Q 3.275858523202972 1.4248e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1151  
   data-arc span      15594 days (42.69 yr)  
   first obs. used      1978-11-29  
   last obs. used      2021-08-09  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .51443  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Aug-24 22:40:19  

Additional Information
 Earth MOID = 1.08278 au 
 Jupiter MOID = 2.16991 au 
 T_jup = 3.337 
[ show covariance matrix ]

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

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 15.11   n/a MPO636381  
diameter diameter 5.059 km 0.222 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
geometric albedo albedo 0.069   0.014 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

21085 (1991 UL4)          Discovered 1991-Oct-18 by Ueda, S., Kaneda, H. at Kushiro
Reference: 20010208/Numbers.arcLast Updated: 2004-04-19

Alternate Designations
 1991 UL4 = 1978 WW1 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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