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21785 Mechain (1999 SS2)
Classification: Main-belt Asteroid          SPK-ID: 2021785
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ]

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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 16 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1715859172238854 1.044e-07  
a 2.77673225301258 2.1659e-08 au
q 2.30028410249427 2.8825e-07 au
i 18.66440308104544 1.1104e-05 deg
node 22.91207768692232 1.9079e-05 deg
peri 359.040918848004 2.6842e-05 deg
M 215.9900261891802 1.8587e-05 deg
tp 2458276.566637244189
9.0743e-05 JED
period 1690.049535927505
n .2130115078564433 2.4923e-09 deg/d
Q 3.253180403530889 2.5376e-08 au
  Orbit Determination Parameters
   # obs. used (total)      503  
   data-arc span      14422 days (39.49 yr)  
   first obs. used      1976-10-22  
   last obs. used      2016-04-17  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .58678  
   data source      ORB  
   producer      Otto Matic  
   solution date      2016-Apr-25 13:37:35  

Additional Information
 Earth MOID = 1.30226 au 
 Jupiter MOID = 2.20227 au 
 T_jup = 3.238 
[ show covariance matrix ]

Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 14.7 mag n/a MPO324511  

21785 Méchain           Discovered 1999 Sept. 21 by M. Tichy at Klet.
Pierre François André Méchain (1744-1804) discovered many comets and deep-sky objects. A colleague and friend of Messier, he contributed much to Messier's catalogue of nebulae. Much of Méchain's career involved geodetic measurements along the Paris meridian, with the idea of defining the meter.
NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character)
Reference: 20020624/MPCPages.arcLast Updated: 2003-10-02

Alternate Designations
 1999 SS2 = 1976 UX5 
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ]
FirstGov 2016-May-04 07:56 UT
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