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24 Themis
Classification: Main-belt Asteroid          SPK-ID: 2000024
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 2457000.5 (2014-Dec-09.0) TDB
Reference: JPL 92 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1258089396666894 2.5709e-08  
a 3.134947262220447 7.7824e-09 AU
q 2.740542871249502 8.1074e-08 AU
i .7522721906473218 2.9327e-06 deg
node 35.92250485382481 0.00022625 deg
peri 106.6713065284752 0.00022658 deg
M 71.67401795563934 1.1768e-05 deg
tp 2456596.851785097262
6.557e-05 JED
period 2027.420277385921
n .1775655516596541 6.612e-10 deg/d
Q 3.529351653191392 8.7615e-09 AU
  Orbit Determination Parameters
   # obs. used (total)      2272  
   data-arc span      59081 days (161.75 yr)  
   first obs. used      1853-04-27  
   last obs. used      2015-01-29  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .65401  
   data source      ORB  
   producer      Otto Matic  
   solution date      2015-Mar-09 13:25:10  

Additional Information
 Earth MOID = 1.75377 AU 
 T_jup = 3.200 
[ 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 7.08 mag n/a PDS3 (MPC 17257)  
magnitude slope G 0.19   n/a PDS3 (MPC 17257) Fit
diameter diameter 198 km n/a J.G. Williams (E-mail September 1990) based on IRTF albedo of 0.067
rotation period rot_per 8.374 h n/a LCDB (Rev. 2015-Feb); Warner et al., 2009 Published Reference List:
[Tedesco, E.F. (1979) PhD Dissertation, New. Mex. State Univ. 280pp.]
[Van Houten-Groeneveld, I.; van Houten, C.J.; Zappala, V. (1979) Astron. Astrophys. Suppl. Ser. 35, 223-232.]
[Harris, A.W.; Young, J.W. (1983) Icarus 54, 59-109.]
[Harris, A.W.; Young, J.W.; Bowell, E.; Martin, L.J.; et al. (1989) Icarus 77, 171-186.]
[Chiorny, V.G.; Shevchenko, V.G.; Krugly, Yu.N.; Velichko, F.P.; Gaftonyuk, N.M. (2007) Planet. Space Sci. 55, 986-997.]
[Ditteon, R.; Hawkins, S. (2007) Minor Planet Bul. 34, 59-64.]
[Higley, S.; Hardersen, P.; Dyvig, R. (2008) Minor Planet Bul. 35, 63-66.]
[Pilcher, F. (2012)]
[Pilcher, F. (2013) Minor Planet Bul. 40, 85-87.]
[Pilcher, F. (2014) Minor Planet Bul. 41, 250-252.]
geometric albedo albedo 0.067   n/a J.G. Williams (E-mail September 1990) IRTF
B-V BV .684 mag .030 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=10; phase (min.=.16, mean=9.29, max.=18.36) deg.
U-B UB .336 mag .024 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=8; phase (min.=.16, mean=8.75, max.=18.36) deg.
Tholen spectral type spec_T C   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo
SMASSII spectral type spec_B B   n/a EAR-A-5-DDR-TAXONOMY-V4.0 based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)

24 Themis          Discovered 1853-Apr-05 by De Gasparis, A. at Naples
Reference: DISCOVERY.DBLast Updated: 2003-08-29

[ show close-approach data ]
Alternate Designations
 1947 BA = 1955 OH 
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
FirstGov 2015-Mar-30 23:02 UT
(server date/time)  
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