Broadband Photometry of Planetary Radar Target 2013 US3.
ATel #11597; Michael Hicks (JPL/CalTech), Jana Chesley (JPL/CalTech), Heath Rhoades (JPL/CalTech)
on 2 May 2018; 21:31 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
The Near-Earth Asteroid (NEA) 2013 US3 was discovered on October 24 2013 by the Mt. Lemmon Survey (MPEC 2013-U46) and has been identified as a Potentially Hazardous Asteroid (PHA) as well as a possible spacecraft mission target (NHATS). The asteroid passed within 0.026 AU (approximately one mean lunar distance) on April 29 2018, representing the best Earth-based apparition until April 2118.
In anticipation of the radar observations scheduled at both the Goldstone and Arecibo facilities, we obtained one night of time-resolved photometry at the JPL Table Mountain Observatory (TMO) 1.0-m telescope as summarized in Table 1. The measured colors (B-R=1.318+/-0.021 mag; V-R=0.450+/-0.020 mag; R-I=0.343+/-0.017 mag) were found to be compatible with an S-type spectral classification (Table 2 and
Figure 1
). After assuming a solar phase parameter G=0.15 and correcting for observational geometry we measured an absolute magnitude H_V=21.14+/-0.02 mag. No clear lightcurve signature was detected in our 2.2 hours of observation (
Figure 2
).
Copyright 2018 California Institute of Technology. Government sponsorship acknowledged.
Table 1: 2013 US3 Observational Circumstances.
UT Time r (AU) delta phase V Filters
[AU] [AU] [deg] [mag]
2018 04 26.26 1.018 0.029 65.5 15.8 BVRI
Table 2: Best-fit SMASS II spectral analogs.
TAXONOMIC CLASS
MISFIT OBJECT NAME (THOLEN) (BUS)
0.442 533 Sara S S
0.444 5534 1941 UN S
0.520 403 Cyane S S
0.633 7 Iris S S
0.754 462 Eriphyla S S
