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19945 (1981 ET31)
Classification: Main-belt Asteroid          SPK-ID: 2019945
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

[ show orbit diagram ]
Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 23 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2310666690932856 3.1796e-08  
a 2.989047056348421 1.5495e-08 au
q 2.298377909274901 1.0058e-07 au
i 9.558226081051336 5.1013e-06 deg
node 178.1145962730338 1.8671e-05 deg
peri 269.706425551195 2.1998e-05 deg
M 315.8856077011031 1.1761e-05 deg
tp 2459431.799852216901
(2021-Aug-05.29985222)
6.2373e-05 TDB
period 1887.546046965867
5.17
1.4677e-05
4.018e-08
d
yr
n .190723823971702 1.483e-09 deg/d
Q 3.679716203421942 1.9075e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1407  
   data-arc span      14633 days (40.06 yr)  
   first obs. used      1981-02-12  
   last obs. used      2021-03-07  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .48139  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 03:09:58  

Additional Information
 Earth MOID = 1.33814 au 
 Jupiter MOID = 1.70329 au 
 T_jup = 3.195 
[ hide covariance matrix ]
Orbital Elements at Epoch 2457511.5 (2016-May-03.0) TDB
Reference: JPL 23 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2257722645740692 3.1319e-08  
q 2.318581382248897 9.8636e-08 au
tp 2457533.998912134653
(2016-May-25.49891213)
6.1442e-05 TDB
node 178.517271360867 1.8559e-05 deg
peri 268.476915359316 2.2227e-05 deg
i 9.574144516549284 5.1132e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      1407  
   data-arc span      14633 days (40.06 yr)  
   first obs. used      1981-02-12  
   last obs. used      2021-03-07  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .48139  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 03:09:58  

Additional Information
 Jupiter MOID = 1.70329 au 
 T_jup = 3.195 
Orbit Covariance (6×6)
  e q tp node peri i
e 9.808701776180221E-16 -3.069570296200267E-15 -6.01347975955543E-13 5.796194334224853E-15 -8.117023594676019E-14 1.142665859105157E-15
q -3.069570296200267E-15 9.729069621241326E-15 1.922709618855585E-12 -1.999192323988066E-14 2.631463875263576E-13 -3.488210307449086E-15
tp -6.01347975955543E-13 1.922709618855585E-12 3.775178988765184E-9 -1.55648242686026E-11 7.557675419808417E-10 3.546270187086657E-12
node 5.796194334224853E-15 -1.999192323988066E-14 -1.55648242686026E-11 3.444243135084962E-10 -3.42220408756481E-10 1.663052068059508E-11
peri -8.117023594676019E-14 2.631463875263576E-13 7.557675419808417E-10 -3.42220408756481E-10 4.940492059675134E-10 -1.577754807636236E-11
i 1.142665859105157E-15 -3.488210307449086E-15 3.546270187086657E-12 1.663052068059508E-11 -1.577754807636236E-11 2.614465835544049E-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 14.10   n/a E2021B10  

19945 (1981 ET31)          Discovered 1981-Mar-02 by Bus, S. J. at Siding Spring
Reference: 20010109/Numbers.arcLast Updated: 2004-04-19

[ show close-approach data ]
Alternate Designations
 1981 ET31 = 1989 TN14 = 1999 RU138 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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