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117P/Helin-Roman-Alu 1
Classification: Jupiter-family Comet          SPK-ID: 1000121
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.


:
Orbital Elements at Epoch 2457447.5 (2016-Feb-29.0) TDB
Reference: JPL K222/20 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2540338573975731 1.1432e-07  
a 4.094732693981368 2.447e-07 au
q 3.054531952717325 6.377e-07 au
i 8.698671836280914 6.4565e-06 deg
node 58.8757087352169 4.184e-05 deg
peri 222.5728019314596 4.9604e-05 deg
M 83.7798159283803 1.9723e-05 deg
tp 2456743.174094847257
(2014-Mar-26.67409485)
0.00013639 TDB
period 3026.472701631889
8.29
0.0002713
7.428e-07
d
yr
n .1189503542542731 1.0663e-08 deg/d
Q 5.134933435245411 3.0687e-07 au

Additional Model Parameters
 Parameter Value Uncertainty (1-sigma) 
A1 [EST] 1.085555971471666E-7 1.121E-8
A2 [EST] 2.620147650827203E-8 4.481E-9
  Orbit Determination Parameters
   # obs. used (total)      3357  
   data-arc span      3860 days (10.57 yr)  
   first obs. used      2010-11-03  
   last obs. used      2021-05-29  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .61059  
   source      ORB  
   producer      Davide Farnocchia  
   solution date      2021-Jun-01 12:04:21  

Additional Information
 Earth MOID = 2.04571 au 
 Jupiter MOID = .25991 au 
 T_jup = 2.967 
[ 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
comet total magnitude M1 6.0   0.7 K222/20 2 parameter fit from 1320 observations, autocmod 2.9c
comet total magnitude slope K1 14.25   n/a K222/20 autocmod 2.9c
comet nuclear magnitude M2 11.4   0.5 K222/20 from 1866 observations, autocmod 2.9c
comet nuclear magnitude slope K2 5.   n/a K222/20 autocmod 2.9c
comet nuclear phase coefficient PC 0.03   n/a K222/20 autocmod 2.9c
diameter diameter 9 km n/a Scotti,J (1994) BAAS 26:1375  

117P/Helin-Roman-Alu 1          Discovered 1989-Oct-02 by Helin, Eleanor, Roman, Brian and Alu, Jeff at Palomar Mountain Observatory, California
Reference: comet.disLast Updated: 2003-08-29

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Alternate Designations
 Perihelion 
Year
(est.)
 New-Style 
Desig
Roman
 Numeral 
Year/
 Letter 
 1989.4   117P/1989 T2   1987 XXXVII   1989w 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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