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238P/Read (2005 U1)
Classification: Encke-type Comet          SPK-ID: 1001676
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 2454616.5 (2008-May-30.0) TDB
Reference: JPL 18 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2531969888951213 5.469e-07  
a 3.161984948654287 4.0958e-07 au
q 2.361379880723327 1.9414e-06 au
i 1.266167215096398 2.4294e-05 deg
node 51.62720266047121 0.00043601 deg
peri 325.6244378511225 0.00045372 deg
M 181.8403079775316 8.2564e-05 deg
tp 2455632.854178155310
(2011-Mar-12.35417816)
0.00061836 TDB
period 2053.70530214976
5.62
0.00039903
1.092e-06
d
yr
n .1752929203733185 3.4059e-08 deg/d
Q 3.962590016585248 5.1328e-07 au

Additional Model Parameters
 Parameter Value Uncertainty (1-sigma) 
A1 [EST] 2.436992850134412E-9 1.078E-9
A2 [EST] -5.277191806895388E-11 6.433E-11
  Orbit Determination Parameters
   # obs. used (total)      214  
   data-arc span      4407 days (12.07 yr)  
   first obs. used      2005-10-23  
   last obs. used      2017-11-16  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      1  
   norm. resid. RMS      .70522  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-15 23:28:01  

Additional Information
 Earth MOID = 1.36176 au 
 Jupiter MOID = 1.4998 au 
 T_jup = 3.154 
[ hide covariance matrix ]
Orbit Covariance (8×8)
  e q tp node peri i A1 A2
e 2.991040323519506E-13 -1.054090819719845E-12 -1.792061938312838E-10 1.420985410852683E-12 -3.758009705514196E-11 -6.018067495518953E-13 4.128527359901805E-16 1.522153710749235E-17
q -1.054090819719845E-12 3.769111596749447E-12 7.211643783154705E-10 -3.033220054153502E-12 1.3769834608848E-10 1.944062786869974E-12 -1.567700102215819E-15 -6.67813793425706E-17
tp -1.792061938312838E-10 7.211643783154705E-10 3.823666765405551E-7 -5.152372645557471E-11 6.882720230191243E-8 1.413250704388243E-10 -3.316382226445451E-13 -3.379489683039622E-14
node 1.420985410852683E-12 -3.033220054153502E-12 -5.152372645557471E-11 1.90102212431387E-7 -1.903946213786086E-7 -3.113901155004143E-9 -1.566957522021546E-15 -2.966175340737453E-16
peri -3.758009705514196E-11 1.3769834608848E-10 6.882720230191243E-8 -1.903946213786086E-7 2.058616489479107E-7 3.181709697583604E-9 -3.522835424095458E-14 -4.087366834440533E-15
i -6.018067495518953E-13 1.944062786869974E-12 1.413250704388243E-10 -3.113901155004143E-9 3.181709697583604E-9 5.901834256176063E-10 -4.16957663963072E-16 1.020767488814359E-17
A1 4.128527359901805E-16 -1.567700102215819E-15 -3.316382226445451E-13 -1.566957522021546E-15 -3.522835424095458E-14 -4.16957663963072E-16 1.162056765179047E-18 4.222394518764492E-20
A2 1.522153710749235E-17 -6.67813793425706E-17 -3.379489683039622E-14 -2.966175340737453E-16 -4.087366834440533E-15 1.020767488814359E-17 4.222394518764492E-20 4.138401283152168E-21

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 10.1   0.7 18 2 parameter fit from 111 observations, autocmod 2.9c
comet total magnitude slope K1 24.   n/a 18 autocmod 2.9c
comet nuclear magnitude M2 17.6   01. 18 from 78 observations, autocmod 2.9c
comet nuclear magnitude slope K2 5.   n/a 18 autocmod 2.9c
comet nuclear phase coefficient PC 0.03   n/a 18 autocmod 2.9c

[ show close-approach data ]
Alternate Designations
 Perihelion 
Year
(est.)
 New-Style 
Desig
Roman
 Numeral 
Year/
 Letter 
 2011.2   238P/2010 N2       
 2005.6   238P/2005 U1       
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]
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