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18754 (1999 GL21)
Classification: Main-belt Asteroid          SPK-ID: 2018754
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 42 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1152905082698942 3.0349e-08  
a 2.394897308272032 8.9528e-09 au
q 2.118788380347147 7.4009e-08 au
i 7.262635613316086 3.4229e-06 deg
node 39.19422869822058 2.6786e-05 deg
peri 252.9872475762483 3.0966e-05 deg
M 235.4471042869539 1.6652e-05 deg
tp 2459668.860325062180
(2022-Mar-30.36032506)
6.302e-05 TDB
period 1353.719767470039
3.71
7.5909e-06
2.078e-08
d
yr
n .2659339167904761 1.4912e-09 deg/d
Q 2.671006236196916 9.985e-09 au
  Orbit Determination Parameters
   # obs. used (total)      2373  
   data-arc span      15507 days (42.46 yr)  
   first obs. used      1978-10-09  
   last obs. used      2021-03-24  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .46943  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-May-04 02:47:01  

Additional Information
 Earth MOID = 1.11462 au 
 Jupiter MOID = 2.48869 au 
 T_jup = 3.510 
[ 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 13.64   n/a E2021B10  
diameter diameter 4.422 km 0.174 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
rotation period rot_per 5.676 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:
[Erasmus, N.; Navarro-Meza, S.; McNeill, A.; Trilling, D.E.; et al. (2020) Ap. J. Suppl. Ser. 247, A13.]
geometric albedo albedo 0.360   0.072 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

18754 (1999 GL21)          Discovered 1999-Apr-15 by LINEAR at Socorro
Reference: 20001111/Numbers.arcLast Updated: 2004-04-19

Alternate Designations
 1999 GL21 = 1978 TB9 = 1989 UT9 = 2000 ON50 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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