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Palomar Spectroscopy of Near-Earth Asteroids 137199 (1999 KX4), 152756 (1999 JV3), 163249 (2002 GT), 163364 (2002 OD20), and 285263 (1998 QE2).

ATel #5132; M. Hicks (JPL/Caltech), K. Lawrence (JPL/Caltech), S. Chesley (JPL/Caltech), J. Chesley (JPL/Caltech), H. Rhoades (JPL/Caltech), S. Elberhar (PCC), A. Carcione (Moorpark), R. Borlase (PCC)
on 14 Jun 2013; 16:26 UT
Credential Certification: Michael D. Hicks (Michael.Hicks@jpl.nasa.gov)

Subjects: Optical, Asteroid, Planet (minor), Solar System Object, Near-Earth Object, Potentially Hazardous Asteroid, Asteroid (Binary)

We obtained long-slit CCD spectrograms of the near-Earth asteroids 137199 (1999 KX4), 152756 (1999 JV3), 163249 (2002 GT), 163364 (2002 OD20), and 285263 (1998 QE2) using the Palomar 5-m Hale Telescope equipped with the facility dual-channel spectrometer on June 05 2013. All of our objects have been scheduled for radar observation at the Arecibo and/or Goldstone Facilities. 2002 GT, 2002 OD20, and 1998 QE2 have been designated as Potentially Hazardous Asteroids by the Minor Planets Center, although they currently pose no significant impact threat. 2002 GT is the 2020 flyby target of the Deep Impact spacecraft.

Table 1 summarizes our observational circumstances, with the expected V magnitude computed assuming a phase parameter G=0.15 using the orbital elements and absolute magnitude H_V maintained by the JPL HORIZONS database. Table 1 also lists the solar analog stars used to generate the composite normalized reflectance spectra, as shown in Figures 1-5 [1] [2] [3] [4] [5].

A comparison of our optical spectra with the 1341 asteroid spectra archived in the SMASS II database (Bus & Binzel 2002) was used to determine taxonomy. Table 2 list the four best-fit SMASS II analogs for each object. We identify 1999 KX4, 1999 JV3, 2002 GT, 2002 OD20, and 1998 QE2 as Sq, Sa, Sq, Sq, and Ch-type asteroids, respectively. 1998 QE2 is a binary asteroid (L. Benner, personal communication) and remains well-placed for lightcurve study from the northern hemisphere through mid-August 2013 (V<18 mag). Collaborative observations with other researchers would be very welcomed.

Copyright 2013. All rights reserved. The research described in this telegram was carried out at the Jet Propulsion Laboratory, under a contract with the National Aeronautics and Space Administration. The student participation was supported by the National Science Foundation under REU grant AST-1156756 to Los Angeles City College.

 
Table 1:  Observational Circumstances. 
 
                                 Solar  Exp.  Int. 
Object Name          r    delta  Phase   V    Time    Solar Analog Star(s) 
                    [AU]   [AU]  [deg] [mag]  [min] 
137199 (1999 KX4)  1.246  0.285   31.7  15.9    14    104-483 
152756 (1999 JV3)  1.079  0.142   59.6  17.0    35    16 Cyg B 
163249 (2002 GT)   1.134  0.160   39.3  16.2   100    101-321, 104-483 
163364 (2002 OD20) 1.094  0.085   20.8  14.7    30    101-321, 104-483 
285263 (1998 QE2)  1.059  0.048   21.5  11.7    14    101-321, 104-483, 107-998 
 
 
Table 2:  Best-fit SMASS II spectral analogs. 
 
                         Taxonomic Class 
Misfit  Object Name      (Tholen)  (Bus) 
 
137199 (1999 KX4) 
 
0.860 6077 Messner                   Sq 
0.869 4261 Gekko                     Sq 
0.901   33 Polyhymnia        S       Sq 
0.938 4051 Hatanaka                  Sq 
 
152756 (1999 JV3) 
 
0.597 1563 Noel                      Sa 
0.610 3474 Linsley                   Sa 
0.644 1667 Pels                      Sa 
0.657 2280 Kunikov                   Sa 
 
163249 (2002 GT) 
 
0.605 1483 Hakoila                   Sq 
0.622 6077 Messner                   Sq 
0.832 7224 Vesnina                   Sq 
0.897 1324 Knysna                    Sq 
 
163364 (2002 OD20) 
 
0.537 1324 Knysna                    Sq 
0.746 7728 Giblin                    Sq 
0.849 1483 Hakoila                   Sq 
0.949 6077 Messner                   Sq 
 
285263 (1998 QE2) 
 
0.163  503 Evelyn            XC      Ch 
0.190  111 Ate               C       Ch 
0.200 3507 Vilas                     Ch 
0.219  868 Lova              C       Ch