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2920 Automedon (1981 JR)
Classification: Jupiter Trojan          SPK-ID: 2002920
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 17 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .02598084387422484 6.7961e-08  
a 5.108261851720505 1.1985e-07 au
q 4.975544898082297 3.3887e-07 au
i 21.12379089106147 8.0135e-06 deg
node 230.9510275013893 1.7966e-05 deg
peri 198.8051717394581 0.00013307 deg
M 168.6323443254911 0.00013042 deg
tp 2455625.138747555923
0.0015375 JED
period 4217.04420776632
n .08536785062319384 3.0044e-09 deg/d
Q 5.240978805358714 1.2297e-07 au
  Orbit Determination Parameters
   # obs. used (total)      1063  
   data-arc span      12765 days (34.95 yr)  
   first obs. used      1981-05-03  
   last obs. used      2016-04-14  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .54506  
   data source      ORB  
   producer      Otto Matic  
   solution date      2016-Apr-25 12:41:38  

Additional Information
 Earth MOID = 3.99003 au 
 Jupiter MOID = .0266863 au 
 T_jup = 2.866 
[ 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 8.8 mag n/a MPO365280  
diameter diameter 111.01 km 7.5 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 13
rotation period rot_per 10.212 h n/a LCDB (Rev. 2016-February); Warner et al., 2009 Published Reference List:
[Molnar, L.A.; Haegert, M.J.; Hoogenboom, K.M. (2008) Minor Planet Bul. 35, 82-84.]
[Mottola, S.; Di Martino, M.; Erikson, A.; Gonano-Beurer, M.; et al. (2011) Astron. J. 141, A170.]
geometric albedo albedo 0.0433   0.007 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 13

2920 Automedon (1981 JR)          Discovered 1981-May-03 by Bowell, E. at Flagstaff (AM)
Discovered at the Anderson Mesa station, which is operated by the Lowell Observatory.
Reference: DISCOVERY.DBLast Updated: 2003-08-29
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ]
FirstGov 2016-Apr-30 15:01 UT
(server date/time)  
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