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C/2021 A4 (NEOWISE)
Classification: Comet          SPK-ID: 1003756
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]

[ hide orbit diagram ]

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 2459260.5 (2021-Feb-15.0) TDB
Reference: JPL 9 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .9741473113584262 8.2837e-05  
a 44.31315528399904 0.14248 au
q 1.145614206282936 1.2707e-05 au
i 111.5780137250092 0.00075347 deg
node 307.0804055607692 0.00040271 deg
peri 204.6414695262359 0.0022118 deg
M 359.889696322532 0.00053936 deg
tp 2459293.512995298466
(2021-Mar-20.01299530)
0.0022077 TDB
period 107745.0777730603
294.99
519.64
1.423
d
yr
n .003341219918725712 1.6114e-05 deg/d
Q 87.48069636171515 0.28127 au

Additional Model Parameters
 Parameter Value Uncertainty (1-sigma) 
A1 [EST] 1.083624587213395E-8 1.727E-9
A2 [EST] 2.075407976949148E-8 3.245E-9
  Orbit Determination Parameters
   # obs. used (total)      656  
   data-arc span      99 days  
   first obs. used      2021-01-03  
   last obs. used      2021-04-12  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      5  
   norm. resid. RMS      .56888  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-May-04 14:10:30  

Additional Information
 Earth MOID = .208801 au 
 Jupiter MOID = 2.3445 au 
 T_jup = -0.367 
[ hide covariance matrix ]
Orbit Covariance (8×8)
  e q tp node peri i A1 A2
e 6.8619584880437E-9 1.051421132931062E-9 -1.828162956257561E-7 -3.332696824991982E-8 -1.830977968968446E-7 6.23346834820871E-8 -7.161716222171433E-14 1.739416713429916E-13
q 1.051421132931062E-9 1.614599574344597E-10 -2.80428476471974E-8 -5.114094664825149E-9 -2.810105834790517E-8 9.564714937171392E-9 -1.130917756695027E-14 2.767000281551322E-14
tp -1.828162956257561E-7 -2.80428476471974E-8 4.874033798460055E-6 8.884800606691638E-7 4.882695414322652E-6 -1.661959949479158E-6 1.916740430603341E-12 -4.723042954091602E-12
node -3.332696824991982E-8 -5.114094664825149E-9 8.884800606691638E-7 1.621728095341689E-7 8.902422776326428E-7 -3.033082125870938E-7 3.536022755561461E-13 -8.731120272735256E-13
peri -1.830977968968446E-7 -2.810105834790517E-8 4.882695414322652E-6 8.902422776326428E-7 4.892104613441107E-6 -1.665186860269585E-6 1.936065389636185E-12 -4.781335001701132E-12
i 6.23346834820871E-8 9.564714937171392E-9 -1.661959949479158E-6 -3.033082125870938E-7 -1.665186860269585E-6 5.677152831831129E-7 -6.524128787381858E-13 1.632192789294467E-12
A1 -7.161716222171433E-14 -1.130917756695027E-14 1.916740430603341E-12 3.536022755561461E-13 1.936065389636185E-12 -6.524128787381858E-13 2.982037930428422E-18 -2.679573744696682E-18
A2 1.739416713429916E-13 2.767000281551322E-14 -4.723042954091602E-12 -8.731120272735256E-13 -4.781335001701132E-12 1.632192789294467E-12 -2.679573744696682E-18 1.053085435778829E-17

Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
comet total magnitude M1 13.6   0.7 9 2 parameter fit from 545 observations, autocmod 2.9c
comet total magnitude slope K1 28.5   n/a 9 autocmod 2.9c
comet nuclear magnitude M2 17.5   0.3 9 from 47 observations, autocmod 2.9c
comet nuclear magnitude slope K2 5.   n/a 9 autocmod 2.9c
comet nuclear phase coefficient PC 0.03   n/a 9 autocmod 2.9c

[ show close-approach data ]
Alternate Designations
 Perihelion 
Year
(est.)
 New-Style 
Desig
Roman
 Numeral 
Year/
 Letter 
 2021.2   C/2021 A4       
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]
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