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4025 Ridley (1981 WU)
Classification: Main-belt Asteroid          SPK-ID: 2004025
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 32 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .167711341988854 2.1012e-08  
a 2.251300796490763 5.4603e-09 au
q 1.873732118690721 4.658e-08 au
i 3.128800840046375 8.0192e-07 deg
node 147.32010822139 1.8465e-05 deg
peri 245.7550022454712 2.0331e-05 deg
M 217.7049672431864 5.7064e-06 deg
tp 2459688.181132191464
(2022-Apr-18.68113219)
2.0118e-05 TDB
period 1233.811217352703
3.38
4.4888e-06
1.229e-08
d
yr
n .2917788353168204 1.0615e-09 deg/d
Q 2.628869474290805 6.3761e-09 au
  Orbit Determination Parameters
   # obs. used (total)      2426  
   data-arc span      16738 days (45.83 yr)  
   first obs. used      1974-09-14  
   last obs. used      2020-07-12  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .45831  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-12 15:50:59  

Additional Information
 Earth MOID = .881123 au 
 Jupiter MOID = 2.80154 au 
 T_jup = 3.606 
[ 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 13.82   n/a E2021B10  
diameter diameter 4.384 km 0.230 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  
rotation period rot_per 28.24 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List:
[Skiff, B.A. (2018) Posting on CALL web site: http://www.minorplanet.info/call.html]
geometric albedo albedo 0.250   0.051 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)  

4025 Ridley (1981 WU)          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 WU = 1974 RO1 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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