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21821 Billryan (1999 TN36)
Classification: Main-belt Asteroid          SPK-ID: 2021821
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbit Diagram
Note: Make sure you have Java enabled on your browser to see the applet. This applet is provided as a 3D orbit visualization tool. The applet was implemented using 2-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances. For accurate long-term ephemerides, please instead use our Horizons system.

Note: If the applet has stopped working because of a recent Java upgrade, here is a possible workaround.
Orbit Viewer

Additional Notes: the orbits shown in the applet are color coded. The planets are white lines, and the asteroid/comet is a blue line. The bright white line indicates the portion of the orbit that is above the ecliptic plane, and the darker portion is below the ecliptic plane. Likewise for the asteroid/comet orbit, the light blue indicates the portion above the ecliptic plane, and the dark blue the portion below the ecliptic plane.

Orbit Viewer applet originally written and kindly provided by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).

Orbital Elements at Epoch 2457600.5 (2016-Jul-31.0) TDB
Reference: JPL 14 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .0847432570120112 4.7161e-08  
a 2.942204996259389 2.3366e-08 au
q 2.692872962079356 1.4001e-07 au
i 2.884932451002216 5.8758e-06 deg
node 127.7040166816603 0.0001035 deg
peri 306.3647606311713 0.00011361 deg
M 75.09433064129108 4.3381e-05 deg
tp 2457215.985723163481
0.00022327 JED
period 1843.350070225314
n .1952965992813274 2.3265e-09 deg/d
Q 3.191537030439421 2.5346e-08 au
  Orbit Determination Parameters
   # obs. used (total)      892  
   data-arc span      8731 days (23.90 yr)  
   first obs. used      1992-05-07  
   last obs. used      2016-04-02  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .51124  
   data source      ORB  
   producer      Otto Matic  
   solution date      2016-Apr-25 13:37:40  

Additional Information
 Earth MOID = 1.70746 au 
 Jupiter MOID = 2.02015 au 
 T_jup = 3.265 
[ show covariance matrix ]

Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 14.7 mag n/a MPO358836  

21821 Billryan           Discovered 1999 Oct. 12 by the Lowell Observatory Near-Earth Object Search at the Anderson Mesa Station.
William H. Ryan (b. 1962) is an astrophysicist at the New Mexico Institute of Mining and Technology's Magdalena Ridge Observatory. Ryan discovered that (3782) Celle has a companion, making it the first identified binary vestoid; and later, that vestoid (3703) Volkonskaya is also binary.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: 20080718/MPCPages.arcLast Updated: 2008-07-18

[ show close-approach data ]
Alternate Designations
 1999 TN36 = 1997 HL12 
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
FirstGov 2016-Apr-29 04:02 UT
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