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21220 (1994 WE4)
Classification: Main-belt Asteroid          SPK-ID: 2021220
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

[ show orbit diagram ]
Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 30 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .10791442747945 2.5959e-08  
a 3.004266425641874 1.6405e-08 au
q 2.680062734322997 7.9265e-08 au
i 11.08449190237332 4.1165e-07 deg
node 65.79778197083067 2.9238e-06 deg
peri 266.7490066162852 7.3191e-06 deg
M 95.18148903718432 7.0738e-06 deg
tp 2458697.629583323319
(2019-Aug-02.12958332)
3.442e-05 TDB
period 1901.980645972887
5.21
1.5579e-05
4.265e-08
d
yr
n .1892763739537715 1.5503e-09 deg/d
Q 3.32847011696075 1.8175e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1637  
   data-arc span      15464 days (42.34 yr)  
   first obs. used      1978-11-01  
   last obs. used      2021-03-04  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .50276  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 03:41:40  

Additional Information
 Earth MOID = 1.69732 au 
 Jupiter MOID = 2.03677 au 
 T_jup = 3.215 
[ 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 13.29   n/a E2021B10  
rotation period rot_per 4.321 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Result based on less than full coverage, so that the period may be wrong by 30 percent or so.
Published Reference List:
[Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2015) Astron. J. 150, A75.]

21220 (1994 WE4)          Discovered 1994-Nov-30 by Kobayashi, T. at Oizumi
Reference: 20010208/Numbers.arcLast Updated: 2004-04-19

Alternate Designations
 1994 WE4 = 1978 VR15 = 1999 VW26 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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