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JPL Small-Body Database Browser
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2154 Underhill (2015 P-L)
Classification: Main-belt Asteroid          SPK-ID: 2002154
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.

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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 27 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .1247787917434568 3.6077e-08  
a 2.634920019810012 1.1202e-08 au
q 2.306137883397473 9.4941e-08 au
i 7.74133763857216 4.3568e-06 deg
node .7157728588747596 2.9906e-05 deg
peri 120.5691552813446 3.4678e-05 deg
M 244.36406661716 1.9044e-05 deg
tp 2459502.310670783132
8.3884e-05 TDB
period 1562.246580254918
n .2304373743236214 1.4695e-09 deg/d
Q 2.96370215622255 1.26e-08 au
  Orbit Determination Parameters
   # obs. used (total)      1809  
   data-arc span      22486 days (61.56 yr)  
   first obs. used      1958-04-08  
   last obs. used      2019-10-31  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .45398  
   source      ORB  
   producer      Otto Matic  
   solution date      2019-Nov-07 02:12:58  

Additional Information
 Earth MOID = 1.33277 au 
 Jupiter MOID = 2.11082 au 
 T_jup = 3.374 
[ 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 13.0   n/a MPO452191  
diameter diameter 12.549 km 0.131 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (  
geometric albedo albedo 0.068   0.021 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (  

2154 Underhill (2015 P-L)          Discovered 1960-Sep-24 by PLS at Palomar
These planets have all been discovered as a result of the Palomar survey of faint minor planets and subsequently identified with planets observed at other oppositions. In Sept. and Oct. 1960, T. Gehrels exposed 130 plates with the 122 cm Schmidt camera at Palomar. In the following years C. J. van Houten and I. van Houten-Groeneveld measured these plates astrometrically and photometrically at Leiden. P. Herget, Cincinnati, computed the orbits of the planets found on the NORC computer, Dahlgren, Virginia, USA.
Note: "planet" implies "minor planet"
Reference: DISCOVERY.DBLast Updated: 2003-08-29

Alternate Designations
 2015 P-L = 1958 GU = 1973 SN4 = 1973 UC4 = 1979 DB 
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
FirstGov 2020-Apr-07 20:43 UT
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