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991 McDonalda (A922 UC)
Classification: Main-belt Asteroid          SPK-ID: 2000991
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 42 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1592876067257917 3.1779e-08  
a 3.139486505601701 1.3176e-08 au
q 2.639405213776487 1.026e-07 au
i 2.069502581425571 3.2665e-06 deg
node 63.23457491796459 0.00010401 deg
peri 254.7511116743975 0.00010457 deg
M 274.5863239083757 1.277e-05 deg
tp 2459682.571293578226
(2022-Apr-13.07129358)
7.3576e-05 TDB
period 2031.825272360327
5.56
1.2791e-05
3.502e-08
d
yr
n .1771805897373231 1.1154e-09 deg/d
Q 3.639567797426915 1.5275e-08 au
  Orbit Determination Parameters
   # obs. used (total)      3346  
   data-arc span      31013 days (84.91 yr)  
   first obs. used      1936-02-20  
   last obs. used      2021-01-17  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .44168  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Feb-24 00:51:33  

Additional Information
 Earth MOID = 1.62515 au 
 Jupiter MOID = 1.66486 au 
 T_jup = 3.190 
[ 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 11.26   n/a E2021B10 IRAS observations used: 15
diameter diameter 38.556 km 0.514 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
geometric albedo albedo 0.040   0.005 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
B-V BV 0.660   0.020 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=11.11 deg.
U-B UB 0.370   0.045 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=11.11 deg.
Tholen spectral type spec_T C:   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 2 color indices

991 McDonalda (A922 UC)          Discovered 1922-Oct-24 by Struve, O. at Williams Bay
Reference: DISCOVERY.DBLast Updated: 2003-08-29

[ show close-approach data ]
Alternate Designations
 A922 UC = 1949 PF = 1950 WG = 1953 GT1 = 1975 EE6 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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