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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.


Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 25 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1173415156090112 4.3553e-08  
a 3.104825153550986 1.9119e-08 au
q 2.740500264332332 1.3238e-07 au
i .730424107400247 4.7121e-06 deg
node 168.9935767150743 0.00026877 deg
peri 11.38622223206056 0.00026929 deg
M 200.0073023270823 1.9655e-05 deg
tp 2460088.579427215583
(2023-May-24.07942722)
0.00011407 TDB
period 1998.269911363133
5.47
1.8457e-05
5.053e-08
d
yr
n .1801558427882366 1.664e-09 deg/d
Q 3.46915004276964 2.1362e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1249  
   data-arc span      9532 days (26.10 yr)  
   first obs. used      1995-01-07  
   last obs. used      2021-02-11  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .52587  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 03:57:01  

Additional Information
 Earth MOID = 1.74314 au 
 Jupiter MOID = 1.49023 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 14.26   n/a E2021B10  

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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