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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 ]

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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 2456729.5 (2014-Mar-13.0) TDB
Reference: JPL K192/5 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .4619470353743215 1.9389e-07  
a 3.735867254747169 4.2854e-07 au
q 2.010094451864709 9.4926e-07 au
i 6.254021454418187 6.2276e-06 deg
node 210.5611153184889 0.00014064 deg
peri 192.7547414922277 0.0001462 deg
M 107.9019198213718 1.4563e-05 deg
tp 2455938.981109850876
(2012-Jan-12.48110985)
9.6313e-05 TDB
period 2637.458174282804
7.22
0.00045382
1.242e-06
d
yr
n .1364950555463856 2.3486e-08 deg/d
Q 5.461640057629629 6.2651e-07 au

Additional Model Parameters
 Parameter Value Uncertainty (1-sigma) 
A1 [EST] 1.586577280354216E-10 1.263E-10
A2 [EST] 3.809412379492953E-10 1.197E-11
A3 [EST] -2.53181412767283E-10 5.772E-11
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)      4900  
   data-arc span      3171 days (8.68 yr)  
   first obs. used      2011-05-03  
   last obs. used      2020-01-07  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .59664  
   source      ORB  
   producer      Javier Roa  
   solution date      2020-Jan-13 10:57:45  

Additional Information
 Earth MOID = 1.0198 au 
 Jupiter MOID = .0201683 au 
 T_jup = 2.887 
 Nongrav. accels. using CO driven g(r) 
[ hide covariance matrix ]
Orbit Covariance (9×9)
  e q tp node peri i A1 A2 A3
e 3.759237141736935E-14 -1.837054160756876E-13 1.060373444302188E-11 2.515352719235274E-12 -6.780806061865158E-12 -1.356558848243293E-13 2.363705166448008E-17 -5.84153426052989E-19 -8.453712355341113E-19
q -1.837054160756876E-13 9.01099106736901E-13 -5.350967426771781E-11 -1.198192899331599E-11 3.330220628297867E-11 6.534604632232409E-13 -1.173015541327167E-16 3.216631691959895E-18 4.011002588069884E-18
tp 1.060373444302188E-11 -5.350967426771781E-11 9.276199828210405E-9 -1.071411033395798E-10 2.022892508300899E-10 -3.819639011736839E-12 8.211559686831987E-15 -4.279623055958599E-16 9.281966616968E-17
node 2.515352719235274E-12 -1.198192899331599E-11 -1.071411033395798E-10 1.978055060856093E-8 -2.006693003878561E-8 -2.528256256748695E-10 1.32782094500351E-15 4.232765855225731E-17 -7.742034317262116E-15
peri -6.780806061865158E-12 3.330220628297867E-11 2.022892508300899E-10 -2.006693003878561E-8 2.137338711869013E-8 2.730491633898382E-10 -4.094088705201894E-15 9.438162278347745E-17 7.840949734782307E-15
i -1.356558848243293E-13 6.534604632232409E-13 -3.819639011736839E-12 -2.528256256748695E-10 2.730491633898382E-10 3.878341254350326E-11 -7.657398636982914E-17 -5.807096288910266E-19 3.765747223478528E-17
A1 2.363705166448008E-17 -1.173015541327167E-16 8.211559686831987E-15 1.32782094500351E-15 -4.094088705201894E-15 -7.657398636982914E-17 1.594664070126171E-20 -5.663773446187249E-22 -4.348273579167132E-22
A2 -5.84153426052989E-19 3.216631691959895E-18 -4.279623055958599E-16 4.232765855225731E-17 9.438162278347745E-17 -5.807096288910266E-19 -5.663773446187249E-22 1.431721179736983E-22 -1.864726309169312E-23
A3 -8.453712355341113E-19 4.011002588069884E-18 9.281966616968E-17 -7.742034317262116E-15 7.840949734782307E-15 3.765747223478528E-17 -4.348273579167132E-22 -1.864726309169312E-23 3.33165623022931E-21

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 8.2   0.9 K192/5 2 parameter fit from 1236 observations, autocmod 2.8
comet total magnitude slope K1 15.5   n/a K192/5 autocmod 2.8
comet nuclear magnitude M2 12.6   0.7 K192/5 from 3468 observations, autocmod 2.8
comet nuclear magnitude slope K2 5.   n/a K192/5 autocmod 2.8
comet nuclear phase coefficient PC 0.03   n/a K192/5 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

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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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