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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 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 24 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1867265327290412 3.0913e-08  
a 2.315806204281081 7.7156e-09 au
q 1.883383741283273 7.047e-08 au
i 3.649482095064577 3.5e-06 deg
node 106.1567077666544 7.0909e-05 deg
peri 163.4677956373842 7.2004e-05 deg
M 109.485009462503 1.3924e-05 deg
tp 2458809.025114267415
(2019-Nov-21.52511427)
4.8937e-05 TDB
period 1287.216940068834
3.52
6.4329e-06
1.761e-08
d
yr
n .2796731372885358 1.3977e-09 deg/d
Q 2.748228667278889 9.1563e-09 au
  Orbit Determination Parameters
   # obs. used (total)      910  
   data-arc span      8304 days (22.74 yr)  
   first obs. used      1998-04-19  
   last obs. used      2021-01-12  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .55473  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Feb-24 08:26:19  

Additional Information
 Earth MOID = .865778 au 
 Jupiter MOID = 2.34816 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 16.07   n/a E2021B55  
rotation period rot_per 5.203 h n/a LCDB (Rev. 2020-October); 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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