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JPL Small-Body Database Browser
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1025 Riema (A923 PG)
Classification: Inner Main-belt Asteroid          SPK-ID: 2001025
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

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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 35 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .03915683495297444 4.2493e-08  
a 1.979193515348724 4.2546e-09 au
q 1.901694561528217 8.4286e-08 au
i 26.86206471802976 5.0303e-06 deg
node 163.3749119534802 7.6249e-06 deg
peri 349.1472155683026 4.9556e-05 deg
M 96.24931309578153 4.9474e-05 deg
tp 2458728.589515387411
0.00013972 TDB
period 1017.023096706365
n .3539742619079764 1.1414e-09 deg/d
Q 2.056692469169231 4.4212e-09 au
  Orbit Determination Parameters
   # obs. used (total)      2258  
   data-arc span      35238 days (96.48 yr)  
   first obs. used      1923-08-13  
   last obs. used      2020-02-03  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .39404  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Feb-22 15:43:44  

Additional Information
 Earth MOID = .911197 au 
 Jupiter MOID = 2.92157 au 
 T_jup = 3.729 
[ 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 12.5   n/a MPO467621  
diameter diameter 4.605 km 0.171 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (  
rotation period rot_per 3.588 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List:
[Stephens, R.D. (2003) Minor Planet Bull. 30, 69-70.]
[Warner, B.D. (2009) Minor Planet Bull. 36, 172-176.]
[Warner, B.D. (2013). Minor Planet Bull. 40, 26-29.]
[Warner, B.D. (2014) Minor Planet Bull. 41, 144-155.]
[Warner, B.D. (2016) Minor Planet Bull. 43, 57-65.]
[Behrend, R. (2017) Observatoire de Geneve web site,]
[Warner, B.D. (2017) Minor Planet Bull. 44, 213-219.]
[Tan, H.; Yeh, T.; Li, B.; Gao, X. (2018) Minor Planet Bull. 45, 57-59.]
geometric albedo albedo 1.000   0.000 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (  
B-V BV 0.714   0.022 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=28.96 deg.
U-B UB 0.294   0.037 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=28.96 deg.
Tholen spectral type spec_T E   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo
SMASSII spectral type spec_B Xe   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)

1025 Riema (A923 PG)          Discovered 1923-Aug-12 by Reinmuth, K. at Heidelberg
Reference: DISCOVERY.DBLast Updated: 2003-08-29

Alternate Designations
 A923 PG = A923 QA 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
FirstGov 2020-Feb-26 12:38 UT
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