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101 Helena
Classification: Main-belt Asteroid          SPK-ID: 2000101
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

[ show orbit diagram ]
Orbital Elements at Epoch 2457000.5 (2014-Dec-09.0) TDB
Reference: JPL 80 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1406613997294871 5.1929e-08  
a 2.582840872419437 9.0005e-09 AU
q 2.21953486002639 1.3554e-07 AU
i 10.20080374462759 5.9523e-06 deg
node 343.4333160623848 2.5954e-05 deg
peri 347.3675296170327 2.9952e-05 deg
M 94.70841436139942 1.5895e-05 deg
tp 2456601.630372893577
(2013-Nov-05.13037289)
6.6414e-05 JED
period 1516.159537951645
4.15
7.9251e-06
2.17e-08
d
yr
n .2374420309925732 1.2411e-09 deg/d
Q 2.946146884812484 1.0267e-08 AU
  Orbit Determination Parameters
   # obs. used (total)      1127  
   data-arc span      52438 days (143.57 yr)  
   first obs. used      1871-03-22  
   last obs. used      2014-10-16  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .57456  
   data source      ORB  
   producer      Otto Matic  
   solution date      2014-Nov-10 12:40:56  

Additional Information
 Earth MOID = 1.21102 AU 
 T_jup = 3.388 
[ 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 8.33 mag n/a IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 15
magnitude slope G 0.35   n/a PDS3 (MPC 17257) Fit
diameter diameter 65.84 km 1.3 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 15
rotation period rot_per 23.080 h n/a Asteroid Lightcurve DataBase (Rev. 2014-Mar-01) Published Reference List:
[Lagerkvist, C.-I.; Rickman, H. (1981) Astron. Astrophys. Suppl. Ser. 45, 177-179.]
[Harris, A.W.; Young, J.W. (1989) Icarus 81, 314-364.]
geometric albedo albedo 0.1898   0.008 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 15
B-V BV .854 mag .020 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=12; phase (min.=3.93, mean=10.53, max.=24.72) deg.
U-B UB .426 mag .033 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.1 #obs=12; phase (min.=3.93, mean=10.53, max.=24.72) 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)

101 Helena          Discovered 1868-Aug-15 by Watson, J. C. at Ann Arbor
Reference: DISCOVERY.DBLast Updated: 2003-08-29

[ show close-approach data ]
Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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