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100831 (1998 HW9)
Classification: Main-belt Asteroid          SPK-ID: 2100831
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 21 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1868397299248254 3.6449e-08  
a 2.315968309474588 8.3426e-09 au
q 1.883253416017902 8.4851e-08 au
i 3.649499257404887 4.3145e-06 deg
node 106.1562729597332 7.2981e-05 deg
peri 163.4833232617539 7.4087e-05 deg
M 53.52454337759161 1.3832e-05 deg
tp 2458809.097407570283
(2019-Nov-21.59740757)
4.9073e-05 TDB
period 1287.352099178216
3.52
6.9559e-06
1.904e-08
d
yr
n .2796437744031386 1.511e-09 deg/d
Q 2.748683202931275 9.9013e-09 au
  Orbit Determination Parameters
   # obs. used (total)      748  
   data-arc span      7767 days (21.26 yr)  
   first obs. used      1998-04-19  
   last obs. used      2019-07-25  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .58813  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Feb-24 01:11:52  

Additional Information
 Earth MOID = .867447 au 
 Jupiter MOID = 2.34873 au 
 T_jup = 3.555 
[ 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 16.0   n/a MPO436469  
rotation period rot_per 5.203 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Result based on less than full coverage, so that the period may be wrong by 30 percent or so.
Published Reference List:
[Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2015) Astron. J. 150, A75.]

100831 (1998 HW9)          Discovered 1998-Apr-19 by Spacewatch at Kitt Peak
Reference: 20051019/Numbers.arcLast Updated: 2005-10-26

[ show close-approach data ]
Alternate Designations
 1998 HW9 = 2001 DD15 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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