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1620 Geographos (1951 RA)
Classification: Apollo [NEO, PHA]          SPK-ID: 2001620
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 614 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .3354538123942714 8.4466e-09  
a 1.245655275529173 7.621e-10 au
q .8277954644238756 1.0632e-08 au
i 13.33739030374745 4.3929e-07 deg
node 337.1856297295336 2.0142e-06 deg
peri 276.9638941992654 2.7784e-06 deg
M 16.89243346055071 2.3529e-06 deg
tp 2459176.672144896673
(2020-Nov-23.17214490)
3.3068e-06 TDB
period 507.8029673599148
1.39
4.6602e-07
1.276e-09
d
yr
n .7089363850543301 6.506e-10 deg/d
Q 1.663515086634471 1.0178e-09 au

Additional Model Parameters
 Parameter Value Uncertainty (1-sigma) 
A2 [EST] -3.145408877822908E-15 9.711E-16
ALN [SET] 1. n/a
NK [SET] 0. n/a
NM [SET] 2. n/a
R0 [SET] 1. n/a
  Orbit Determination Parameters
   # obs. used (total)      4558  
   # delay obs. used      3  
   # Doppler obs. used      4  
   data-arc span      25053 days (68.59 yr)  
   first obs. used      1951-09-14  
   last obs. used      2020-04-17  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .34034  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Apr-21 13:55:39  

Additional Information
 Earth MOID = .0292213 au 
 Jupiter MOID = 3.45646 au 
 T_jup = 5.074 
 Nongravitational accels. using nonstandard g(r) = (1 au/ r)^2 
[ 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 15.3   n/a MPO502169 IRAS observations used: 2
diameter diameter 2.56 km 0.15 Hudson & Ostro, Icarus 193 (2008) 20-38  
extent extent 5.0x2.0x2.1 km 0.15 Hudson & Ostro, Icarus 193 (2008) 20-38  
rotation period rot_per 5.22204 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List:
[Dunlap, J.L. (1974) Astron. J. 79, 324-332.]
[Michalowski, T.; Kwiatkowski, T.; Borczyk, W.; Pych, W. (1994) Acta Astronomica 44, 223-226.]
[Kwiatkowski, T. (1995) Astron. Astrophys. 294, 274-277.]
[Magnusson, P.; Dahlgren, M.; Barucci, M.A.; Jorda, L.; et al. (1996) Icarus 123, 227-244.]
[Hudson, R.S.; Ostro, S.J. (1999) Icarus 140, 369-378.]
[Kaasalainen, M.; Torppa, J.; Muinonen, K. (2001) Icarus 153, 37-51.]
[Behrend, R. (2008) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html]
[Durech, J.; Vokrouhlicky, D.; Kaasalainen, M.; Higgins, D.; et al. (2008). Astron. Astrophys. 489, L25-28.]
[Higgins, D.; Pravec, P.; Kusnirak, P.; Hornoch, K.; Brinsfield, J.W.; Allen, B.; Warner, B.D. (2008) Minor Planet Bull. 35, 123-126.]
[Polishook, D. (2009) Minor Planet Bull. 36, 119-120.]
[Hamanowa, H.; Hamanowa, H. (2011) http://www2.ocn.ne.jp/~hamaten/astlcdata.htm]
[Behrend, R. (2015) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html]
[Warner, B.D. (2016) Minor Planet Bull. 43, 143-154.]
[Skiff, B.A.; McLelland, K.P.; Sanborn, J.J.; Pravec, P.; Koehn, B.W. (2019) Minor Plantet Bull. 46, 238-265.]
[Warner, B.D.; Stephens, R.D. (2019) Minor Planet Bull. 46, 304-314.]
[Warner, B.D.; Stephens, R.D. (2020) Minor Planet Bull. 47, 23-34.]
[Warner, B.D.; Stephens, R.D. (2020) Minor Planet Bull. 47, 105-120.]
geometric albedo albedo 0.290   0.038 urn:nasa:pds:neowise_diameters_albedos::2.0[neos] (http://adsabs.harvard.edu/abs/2015ApJ...814..117N)  
B-V BV 0.862   0.034 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=7; phase (min.=17.27, mean=33.74, max.=52.91) deg.
U-B UB 0.471   0.053 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=4; phase (min.=36.47, mean=37.14, max.=37.75) deg.
Tholen spectral type spec_T S   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 4 color indices; used ground-based radiometric albedo
SMASSII spectral type spec_B S   n/a EAR-A-5-DDR-TAXONOMY-V4.0 based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)

1620 Geographos (1951 RA)          Discovered 1951-Sep-14 by Wilson, A. G. and Minkowski, R. at Palomar
Reference: DISCOVERY.DBLast Updated: 2003-08-29

[ show close-approach data ]
Alternate Designations
 1951 RA = 1983 CY3 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]
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