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JPL Small-Body Database Browser
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21985 Sejna (1999 XG15)
Classification: Main-belt Asteroid          SPK-ID: 2021985
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.


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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 20 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1172459787447276 5.2777e-08  
a 3.105083563500719 2.2229e-08 au
q 2.741025002013911 1.6412e-07 au
i .7303868657056767 5.5546e-06 deg
node 168.9917457368745 0.00036409 deg
peri 11.47541975029636 0.00036463 deg
M 163.8679704362188 2.061e-05 deg
tp 2458090.796345351757
(2017-Dec-03.29634535)
0.00011162 TDB
period 1998.519386073896
5.47
2.1461e-05
5.876e-08
d
yr
n .1801333539762265 1.9344e-09 deg/d
Q 3.469142124987528 2.4836e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1039  
   data-arc span      8891 days (24.34 yr)  
   first obs. used      1995-01-07  
   last obs. used      2019-05-12  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .53806  
   source      ORB  
   producer      Otto Matic  
   solution date      2019-May-30 03:03:59  

Additional Information
 Earth MOID = 1.74413 au 
 Jupiter MOID = 1.49121 au 
 T_jup = 3.210 
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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 14.2   n/a MPO431754  

21985 Šejna           Discovered 1999 Dec. 2 by L. Šarounová at Ondřejov.
Karel Šejna (1896-1982) was the conductor of the Czech Philharmonic Orchestra during 1938-1972 and cocreator of the era of Talich and Ančerl. He was a significiant interpreter of Mahler, Wagner and Bruckner, and his recordings of the compositions of Smetana, Dvořák, Fibich and Suk are superb.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: 20020427/MPCPages.arcLast Updated: 2003-10-02

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Alternate Designations
 1999 XG15 = 1996 FY16 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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