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2261 Keeler (1977 HC)
Classification: Main-belt Asteroid          SPK-ID: 2002261
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

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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 2459396.5 (2021-Jul-01.0) TDB
Reference: JPL 35 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .235972470508733 1.4478e-08  
a 2.37821669568039 5.679e-09 au
q 1.817023026595573 3.629e-08 au
i 22.74090457406673 2.8491e-07 deg
node 102.7449404223726 2.0588e-06 deg
peri 99.44182416797452 2.9857e-06 deg
M 18.59704393149942 3.2388e-06 deg
tp 2459327.298265716349
(2021-Apr-22.79826572)
1.1984e-05 TDB
period 1339.601306201025
3.67
4.7983e-06
1.314e-08
d
yr
n .2687366743624071 9.6259e-10 deg/d
Q 2.939410364765207 7.0191e-09 au
  Orbit Determination Parameters
   # obs. used (total)      3345  
   data-arc span      16139 days (44.19 yr)  
   first obs. used      1977-04-21  
   last obs. used      2021-06-28  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .34144  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Jul-08 13:31:23  

Additional Information
 Earth MOID = .949181 au 
 Jupiter MOID = 2.43002 au 
 T_jup = 3.400 
[ show covariance matrix ]

Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
absolute magnitude H 12.98   n/a MPO614063  
diameter diameter 7.323 km 0.209 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)  
rotation period rot_per 23.10 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:
[Warner, B.D.; Pravec, P.; Kusnirak, P.; Pray, D.P.; et al. (2011) Minor Planet Bull. 38, 3.]
[Pal, A.; Szakats, R.; Kiss, C.; Bodi, A.; et al. (2019) Ap. J. Supl. Ser. 247, id.26.]
geometric albedo albedo 0.266   0.047 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)  

2261 Keeler (1977 HC)          Discovered 1977-Apr-20 by Klemola, A. R. at Mount Hamilton
Reference: DISCOVERY.DBLast Updated: 2003-08-29
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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