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

[ show orbit diagram ]
Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 25 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1725669640020165 5.5225e-08  
a 2.775622291136937 1.7852e-08 au
q 2.296641579139115 1.539e-07 au
i 18.6675323500691 6.3132e-06 deg
node 22.89487332805621 1.4016e-05 deg
peri 358.8499717525464 1.9474e-05 deg
M 197.0488328758567 1.6627e-05 deg
tp 2459965.028978632885
(2023-Jan-20.52897863)
8.2769e-05 TDB
period 1689.036274886918
4.62
1.6295e-05
4.461e-08
d
yr
n .2131392944915302 2.0562e-09 deg/d
Q 3.25460300313476 2.0932e-08 au
  Orbit Determination Parameters
   # obs. used (total)      758  
   data-arc span      15892 days (43.51 yr)  
   first obs. used      1976-10-22  
   last obs. used      2020-04-26  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .52013  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 03:53:24  

Additional Information
 Earth MOID = 1.29865 au 
 Jupiter MOID = 2.20703 au 
 T_jup = 3.238 
[ 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 14.68   n/a E2021B10  
diameter diameter 4.488 km 0.362 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
geometric albedo albedo 0.152   0.028 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

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 | Mission Design | Physical Parameters | Discovery Circumstances ]
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