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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 2456970.5 (2014-Nov-09.0) TDB
Reference: JPL K192/21 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .461659097412254 1.8094e-07  
a 3.736357716665463 3.4865e-07 au
q 2.011434185580375 8.5811e-07 au
i 6.252793881955874 5.3943e-06 deg
node 210.5626387396034 4.1175e-05 deg
peri 192.7561165891618 4.9985e-05 deg
M 140.8164144526972 1.3612e-05 deg
tp 2455938.637377991260
(2012-Jan-12.13737799)
0.00011084 TDB
period 2637.977577876264
7.22
0.00036924
1.011e-06
d
yr
n .1364681804042559 1.9101e-08 deg/d
Q 5.461281247750552 5.0961e-07 au

Additional Model Parameters
 Parameter Value Uncertainty (1-sigma) 
A1 [EST] -9.097066926152616E-10 1.094E-10
A2 [EST] 3.480228545313418E-10 1.129E-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)      5533  
   data-arc span      3311 days (9.07 yr)  
   first obs. used      2011-05-03  
   last obs. used      2020-05-26  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .60238  
   source      ORB  
   producer      Javier Roa  
   solution date      2021-Feb-03 22:22:20  

Additional Information
 Earth MOID = 1.02031 au 
 Jupiter MOID = .0215841 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 8.8   0.8 K192/21 2 parameter fit from 1810 observations, autocmod 2.8
comet total magnitude slope K1 13.75   n/a K192/21 autocmod 2.8
comet nuclear magnitude M2 12.6   0.7 K192/21 from 3507 observations, autocmod 2.8
comet nuclear magnitude slope K2 5.   n/a K192/21 autocmod 2.8
comet nuclear phase coefficient PC 0.03   n/a K192/21 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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