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JPL Small-Body Database Browser
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21148 Billramsey (1993 HN1)
Classification: Main-belt Asteroid          SPK-ID: 2021148
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 27 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1852524535412124 4.0282e-08  
a 2.691206018975235 1.2338e-08 au
q 2.192653500975194 1.1026e-07 au
i 12.86959744364348 4.5159e-06 deg
node 159.57772813877 1.6429e-05 deg
peri 36.35563173278638 1.9127e-05 deg
M 58.31990345615978 1.0748e-05 deg
tp 2458739.263930629342
(2019-Sep-12.76393063)
4.7295e-05 TDB
period 1612.57099892376
4.41
1.109e-05
3.036e-08
d
yr
n .2232459843568228 1.5353e-09 deg/d
Q 3.189758536975276 1.4624e-08 au
  Orbit Determination Parameters
   # obs. used (total)      2126  
   data-arc span      9762 days (26.73 yr)  
   first obs. used      1993-04-16  
   last obs. used      2020-01-07  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .45613  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Jan-29 01:29:24  

Additional Information
 Earth MOID = 1.20697 au 
 Jupiter MOID = 1.80334 au 
 T_jup = 3.311 
[ 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 13.8   n/a MPO474043  
diameter diameter 9.925 km 0.069 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
geometric albedo albedo 0.038   0.008 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

21148 Billramsey           Discovered 1993 Apr. 16 by C. S. Shoemaker and E. M. Shoemaker at Palomar.
William D. Ramsey (b. 1934) helped organize and inventory the Palomar Observatory's 1.2-m Oschin Telescope plate archive. He also helped refurbish for public display the famous Michelson 6-meter interferometer, which was used atop the Hooker 2.5-m telescope at the Mt. Wilson Observatory.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: 20030318/MPCPages.arcLast Updated: 2003-10-02

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Alternate Designations
 1993 HN1 = 1999 TW92 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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