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3944 Halliday (1981 WP1)
Classification: Main-belt Asteroid          SPK-ID: 2003944
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.


Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 30 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1513691813093416 1.1956e-08  
a 2.369153699186554 7.2076e-09 au
q 2.010536843344687 3.0051e-08 au
i 7.547333475821357 5.3546e-07 deg
node 69.57493606583905 2.8554e-06 deg
peri 288.0459078547315 7.2416e-06 deg
M 321.6447965080793 8.9357e-06 deg
tp 2459342.409043283542
(2021-May-07.90904328)
3.3308e-05 TDB
period 1331.951102614702
3.65
6.0782e-06
1.664e-08
d
yr
n .2702801921882101 1.2334e-09 deg/d
Q 2.727770555028421 8.2986e-09 au
  Orbit Determination Parameters
   # obs. used (total)      2576  
   data-arc span      15724 days (43.05 yr)  
   first obs. used      1977-09-23  
   last obs. used      2020-10-11  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .43639  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-12 15:45:13  

Additional Information
 Earth MOID = 1.02089 au 
 Jupiter MOID = 2.74577 au 
 T_jup = 3.519 
[ 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 13.27   n/a E2021B10  
diameter diameter 5.873 km 0.181 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)  
rotation period rot_per 5.565 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.]
geometric albedo albedo 0.295   0.075 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)  

3944 Halliday (1981 WP1)          Discovered 1981-Nov-24 by Bowell, E. at Flagstaff (AM)
Discovered at the Anderson Mesa station, which is operated by the Lowell Observatory.
Reference: DISCOVERY.DBLast Updated: 2003-08-29

[ show close-approach data ]
Alternate Designations
 1981 WP1 = 1977 SH3 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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