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11781 Alexroberts (1966 PL)
Classification: Main-belt Asteroid          SPK-ID: 2011781
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

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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 32 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1241043341710578 1.4083e-08  
a 2.359820237698377 6.571e-09 au
q 2.066956318335433 3.4828e-08 au
i 7.31160379892745 7.0103e-07 deg
node 123.3327619762263 7.4648e-06 deg
peri 168.1806395167396 1.1994e-05 deg
M 18.12589749160761 9.4069e-06 deg
tp 2459133.832552494885
(2020-Oct-11.33255249)
3.4578e-05 TDB
period 1324.087875535749
3.63
5.5304e-06
1.514e-08
d
yr
n .2718852778969355 1.1356e-09 deg/d
Q 2.652684157061322 7.3865e-09 au
  Orbit Determination Parameters
   # obs. used (total)      2397  
   data-arc span      19763 days (54.11 yr)  
   first obs. used      1966-08-07  
   last obs. used      2020-09-15  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .44982  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-12 22:57:27  

Additional Information
 Earth MOID = 1.04945 au 
 Jupiter MOID = 2.51328 au 
 T_jup = 3.531 
[ 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 14.02   n/a E2021B10  
diameter diameter 3.783 km 0.200 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
rotation period rot_per 4.187 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 0.409   0.078 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

11781 Alexroberts           Discovered 1966 Aug. 7 at Bloemfontein.
Scots-born Alexander William Roberts (1857-1938) emigrated in 1883 to South Africa, where he taught at and became principal of Lovedale Training School in Eastern Cape Province. He was one of the most prolific observers of variable stars in the southern hemisphere, and his records are maintained at the Boyden Observatory.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: 20060809/MPCPages.arcLast Updated: 2007-08-08

Alternate Designations
 1966 PL = 1994 CL10 = 1998 HU139 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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