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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 ]

[ show orbit diagram ]
Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 25 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1867265323675676 3.0828e-08  
a 2.315806200560516 7.7025e-09 au
q 1.883383739094539 7.0298e-08 au
i 3.649482176768663 3.4926e-06 deg
node 106.1567078456395 7.0901e-05 deg
peri 163.4677948251302 7.1995e-05 deg
M 109.4850108210334 1.391e-05 deg
tp 2458809.025110353264
(2019-Nov-21.52511035)
4.8889e-05 TDB
period 1287.216936966777
3.52
6.4221e-06
1.758e-08
d
yr
n .2796731379625185 1.3953e-09 deg/d
Q 2.748228662026492 9.1408e-09 au
  Orbit Determination Parameters
   # obs. used (total)      914  
   data-arc span      8304 days (22.74 yr)  
   first obs. used      1998-04-19  
   last obs. used      2021-01-12  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .55367  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 15:33:58  

Additional Information
 Earth MOID = .865778 au 
 Jupiter MOID = 2.34816 au 
 T_jup = 3.555 
[ hide covariance matrix ]
Orbital Elements at Epoch 2457393.5 (2016-Jan-06.0) TDB
Reference: JPL 25 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1862065568757834 3.0836e-08  
q 1.884946242088466 7.029e-08 au
tp 2457521.567432241048
(2016-May-13.06743224)
4.6768e-05 TDB
node 106.1674610899196 7.0919e-05 deg
peri 163.5323668228711 7.2019e-05 deg
i 3.648813222689412 3.4916e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      914  
   data-arc span      8304 days (22.74 yr)  
   first obs. used      1998-04-19  
   last obs. used      2021-01-12  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .55367  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-13 15:33:58  

Additional Information
 Jupiter MOID = 2.34816 au 
 T_jup = 3.555 
Orbit Covariance (6×6)
  e q tp node peri i
e 9.508450856612161E-16 -2.159139078408216E-15 2.842978829882669E-14 4.688657733075801E-15 -4.081475845235486E-15 4.40695595807174E-16
q -2.159139078408216E-15 4.940626671653176E-15 2.17280162488195E-14 -1.163212728678798E-14 3.06144076675345E-14 -9.475596179452491E-16
tp 2.842978829882669E-14 2.17280162488195E-14 2.187202695875261E-9 -1.203881862923965E-11 6.097059706755258E-10 5.666022949333232E-13
node 4.688657733075801E-15 -1.163212728678798E-14 -1.203881862923965E-11 5.029520165965063E-9 -5.022302906360399E-9 1.676908727178186E-11
peri -4.081475845235486E-15 3.06144076675345E-14 6.097059706755258E-10 -5.022302906360399E-9 5.186781251061955E-9 -1.658920244574083E-11
i 4.40695595807174E-16 -9.475596179452491E-16 5.666022949333232E-13 1.676908727178186E-11 -1.658920244574083E-11 1.219110649240346E-11

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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