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JPL Small-Body Database Browser
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78P/Gehrels 2
Classification: Jupiter-family Comet          SPK-ID: 1000030
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

[ show orbit diagram ]
:
Orbital Elements at Epoch 2456814.5 (2014-Jun-06.0) TDB
Reference: JPL K192/6 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .4618558613648292 3.9734e-08  
a 3.735968952458115 4.3075e-08 au
q 2.010489793888314 1.5448e-07 au
i 6.253701577858871 5.8636e-06 deg
node 210.561427869644 4.1597e-05 deg
peri 192.7542097419106 4.9722e-05 deg
M 119.5132380713642 1.267e-05 deg
tp 2455938.877672825137
(2012-Jan-12.37767283)
8.049e-05 TDB
period 2637.565870273909
7.22
4.5616e-05
1.249e-07
d
yr
n .1364894822371258 2.3605e-09 deg/d
Q 5.461448111027916 6.2969e-08 au

Additional Model Parameters
 Parameter Value Uncertainty (1-sigma) 
ALN [SET] .0408373333128795 n/a
NK [SET] 2.6 n/a
NM [SET] 2. n/a
NN [SET] 3. n/a
R0 [SET] 5. n/a
  Orbit Determination Parameters
   # obs. used (total)      5018  
   data-arc span      3199 days (8.76 yr)  
   first obs. used      2011-05-03  
   last obs. used      2020-02-04  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .59703  
   source      ORB  
   producer      Javier Roa  
   solution date      2020-Feb-05 17:46:05  

Additional Information
 Earth MOID = 1.01961 au 
 Jupiter MOID = .0207217 au 
 T_jup = 2.887 
[ 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 8.4   0.8 K192/6 2 parameter fit from 1442 observations, autocmod 2.8
comet total magnitude slope K1 15.   n/a K192/6 autocmod 2.8
comet nuclear magnitude M2 12.6   0.7 K192/6 from 3476 observations, autocmod 2.8
comet nuclear magnitude slope K2 5.   n/a K192/6 autocmod 2.8
comet nuclear phase coefficient PC 0.03   n/a K192/6 autocmod 2.8

78P/Gehrels 2          Discovered 1973-Sep-29 by Gehrels, Tom
discovered on plate/photo taken on discovery date as well as 9/30, 10/4
Reference: comet.disLast Updated: 2003-08-29

[ show close-approach data ]
Alternate Designations
 Perihelion 
Year
(est.)
 New-Style 
Desig
Roman
 Numeral 
Year/
 Letter 
 1990.4       1989 XVII   1989n 
 1983.1   78P/1981 L1   1981 XVII   1981f 
 1975.9   78P/1973 S1   1973 XI   1973n 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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