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18691 (1998 HE1)
Classification: Main-belt Asteroid          SPK-ID: 2018691
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 33 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1283743395413476 3.9289e-08  
a 3.193796238687159 2.1331e-08 au
q 2.783794755916055 1.281e-07 au
i 7.641473508481569 5.6167e-06 deg
node 10.50972143906826 3.2251e-05 deg
peri 278.6031483321703 4.0377e-05 deg
M 277.8661328827434 2.7465e-05 deg
tp 2459676.140694949381
(2022-Apr-06.64069495)
0.00016058 TDB
period 2084.775211391466
5.71
2.0886e-05
5.718e-08
d
yr
n .1726804875810668 1.73e-09 deg/d
Q 3.603797721458263 2.4069e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1460  
   data-arc span      10578 days (28.96 yr)  
   first obs. used      1992-03-30  
   last obs. used      2021-03-16  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .51668  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 02:35:10  

Additional Information
 Earth MOID = 1.77941 au 
 Jupiter MOID = 1.65675 au 
 T_jup = 3.169 
[ 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
absolute magnitude H 13.3   n/a MPO435873  
diameter diameter 5.609 km 0.328 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
geometric albedo albedo 0.323   0.083 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

18691 (1998 HE1)          Discovered 1998-Apr-17 by Beijing Schmidt CCD Asteroid Program at Xinglong
Reference: 20001111/Numbers.arcLast Updated: 2004-04-19

[ show close-approach data ]
Alternate Designations
 1998 HE1 = 1992 FM3 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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