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JPL Small-Body Database Browser
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124 Alkeste (A872 QA)
Classification: Main-belt Asteroid          SPK-ID: 2000124
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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For accurate long-term ephemerides, please instead use our Horizons system.This orbit viewer was implemented using two-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances.

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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 126 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .07551614015900317 3.5539e-08  
a 2.629926724788252 6.58e-09 au
q 2.431324809631234 9.3508e-08 au
i 2.957464185626859 4.1493e-06 deg
node 187.9747942410571 6.8127e-05 deg
peri 62.15468269484589 7.3211e-05 deg
M 306.4612726568678 2.8104e-05 deg
tp 2459232.175144212435
0.00012187 TDB
period 1557.80789076181
n .2310939635977516 8.6729e-10 deg/d
Q 2.82852863994527 7.0769e-09 au
  Orbit Determination Parameters
   # obs. used (total)      3279  
   data-arc span      53935 days (147.67 yr)  
   first obs. used      1872-08-24  
   last obs. used      2020-04-25  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .50224  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-May-20 00:59:13  

Additional Information
 Earth MOID = 1.41902 au 
 Jupiter MOID = 2.18185 au 
 T_jup = 3.394 
[ show covariance matrix ]

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

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 8.1   n/a MPO502153 IRAS observations used: 12
magnitude slope G 0.19   n/a PDS3 (MPC 17257) Fit
diameter diameter 88.648 km 1.651 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (  
rotation period rot_per 9.906 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List:
[Harris, A.W.; Young, J.W. (1983) Icarus 54, 59-109.]
[Shevchenko, V.G.; Bel'skaya, I.N.; Krugly, Yu.N.; Chiorny, V.G.; Gaftonyuk, N.M. (2002) Icarus 155, 365-374.]
[Behrend, R. (2007) Observatoire de Geneve web site,]
[Pilcher, F. (2016) Minor Planet Bull. 43, 296-299.]
geometric albedo albedo 0.128   0.014 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (  
B-V BV 0.844   0.019 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=6; phase (min.=4.53, mean=15.83, max.=22.07) deg.
U-B UB 0.424   0.032 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=6; phase (min.=4.53, mean=14.22, max.=20.37) deg.
Tholen spectral type spec_T S   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo
SMASSII spectral type spec_B S   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)

124 Alkeste (A872 QA)          Discovered 1872-Aug-23 by Peters, C. H. F. at Clinton
Reference: DISCOVERY.DBLast Updated: 2003-08-29

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