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21625 Seira (1999 NN2)
Classification: Main-belt Asteroid          SPK-ID: 2021625
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 11 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2252851861499564 5.5301e-08  
a 3.119526681050672 2.5062e-08 au
q 2.416743532010416 1.7063e-07 au
i 15.64296421933186 7.3263e-06 deg
node 260.8021964269815 2.2449e-05 deg
peri 131.4147819902153 3.0004e-05 deg
M 288.4744158912535 1.9396e-05 deg
tp 2459600.343827361465
(2022-Jan-20.84382736)
0.00011196 TDB
period 2012.479585364551
5.51
2.4252e-05
6.64e-08
d
yr
n .1788838021603026 2.1557e-09 deg/d
Q 3.822309830090928 3.0708e-08 au
  Orbit Determination Parameters
   # obs. used (total)      663  
   data-arc span      25008 days (68.47 yr)  
   first obs. used      1950-12-11  
   last obs. used      2019-05-31  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .53042  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Nov-13 01:55:52  

Additional Information
 Earth MOID = 1.45436 au 
 Jupiter MOID = 1.74156 au 
 T_jup = 3.121 
[ show covariance matrix ]

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 14.0   n/a MPO395211  
diameter diameter 3.924 km 0.283 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
rotation period rot_per 3.084 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.]
geometric albedo albedo 0.346   0.076 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

21625 Seira           Discovered 1999 July 12 by the Lincoln Laboratory Near-Earth Asteroid Research Team at Socorro.
Seira Shimoyama (b. 1988) was awarded first place in the 2006 Intel International Science and Engineering Fair for her zoology project. She attends the Urawa Daiichi Girls High School, Urawa-city, Saitama Prefecture, Japan.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: 20060711/MPCPages.arcLast Updated: 2006-07-17

[ show close-approach data ]
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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