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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 
[ show covariance matrix ]

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

[ hide close-approach data ]
Close-Approach Data   ...sorted by Date/Time (TDB)
Date/Time (TDB) Time Uncertainty
(days_HH:MM)
Body Nominal Distance (au) Minimum Distance (au) Maximum Distance (au) V-relative (km/s) V-infinity (km/s) JD (TDB) Time Uncertainty (minutes) Semi-major axis (km) Semi-minor axis (km) range-LOV angle (deg) N-sigma BP Orbit Ref. Reference Modified
2021-Feb-12 10:21 < 00:01 Earth 0.43376595381815 0.433743746399178 0.433788161237171 54.8500463873432 54.8499343970608 2459257.931341885 0.0429622029186312 1107.41764413527 23.3417365624284 0.406644305049531 59428.9050162208 T 9 CATAB v2.0g-lin.ifort 2021-May-04 14:10:38 2021-May-04 14:10

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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