Broadband Photometry of 2007 LE: A Binary Near-Earth Asteroid
ATel #4188; M. Hicks (JPL/Caltech), W. Smythe (JPL/Caltech), D. Dombroski (LACC), T. Davtyan (LACC), S. Teague (VCC), C. Strojia (VVC)
on 19 Jun 2012; 22:29 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)
The near-Earth asteroid 2007 LE was discovered on June 2, 2007 by the LINEAR NEO survey (MPEC 2007-L21). The object passed within 0.048 AU of the Earth on June 02 2012 and has been designated as a Potentially Hazardous Asteroid (PHA) my the Minor Planet Center.
We obtained 3 nights of time-resolved photometry at the JPL Table Mountain Observatory (TMO) 0.6-m telescope, as summarized in Table 1, and included one night of BVRI imaging
[Figure 1].
We found that 2007 LE's colors (B-R=1.082+/-0.020 mag; V-R=0.397+/-0.010 mag; R-I=0.345+/-0.010 mag) most compatible with a C-type spectral classification, as summarized in Table 2.
A solar phase curve was generated and used to fit a standard H-G model (H_R=18.61, g=0.04), as shown in
Figure 2.
Our derived g value is consistent with the object's spectral classification and implies a low optical albedo. We estimate an absolute magnitude H_V=19.01+/-0.05 mag and size D=0.94+/-0.01 km, assuming an albedo rho=0.05.
The dispersion in the phased lightcurve suggested strongly that 2007 LE was a binary system, with variations in observed flux caused by an unresolved, tidally locked secondary companion. The binary nature of 2007 LE was first noted by the JPL Planetary Radar Team (Lance Benner, personal communication). The TMO photometry was fitted a 2-period lightcurve model as described by Pravec et al. (2000) and found P_1=2.603+/-0.005 hr, P_2=33.5+/-0.5 hr, though the model is not well constrained
[Figure 3].
2007 LE will remain available to optical observers (V < 20 mag, dec < -30 deg) through mid July 2012 and we welcome any potential collaborations.
Copyright 2012. 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 0852088 to Cal State LA.
Table 1: Observational Circumstances.
UT Time r (AU) delta phase V Filters Observers
[AU] [AU] [deg] [mag]
2012 06 01.24 1.044 0.049 51.8 14.7 R Hicks
2012 06 03.31 1.057 0.049 29.1 14.0 BVRI Dombroski/Davtyan
2012 06 05.28 1.077 0.066 19.9 14.4 R Smythe
Table 2: Best-fit SMASS II spectral analogs.
TAXONOMIC CLASS
MISFIT OBJECT NAME (THOLEN) (BUS)
1.222 3389 Sinzot C
1.623 3762 Amaravella X
1.630 143 Adria C Xc
1.668 479 Caprera C
1.888 2930 Euripides C
