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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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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.


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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 22 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1868397368210783 3.1846e-08  
a 2.315968308144007 7.8596e-09 au
q 1.883253398964422 7.2952e-08 au
i 3.649495287419743 3.7148e-06 deg
node 106.156258711909 7.2358e-05 deg
peri 163.4833382835386 7.3442e-05 deg
M 53.52454373176505 1.3818e-05 deg
tp 2458809.097406468715
(2019-Nov-21.59740647)
4.901e-05 TDB
period 1287.352098068792
3.52
6.5533e-06
1.794e-08
d
yr
n .2796437746441321 1.4235e-09 deg/d
Q 2.748683217323591 9.3281e-09 au
  Orbit Determination Parameters
   # obs. used (total)      872  
   data-arc span      8224 days (22.52 yr)  
   first obs. used      1998-04-19  
   last obs. used      2020-10-24  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .55891  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Nov-12 20:04:00  

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

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