Tracking the Polyrhythm: Broadband Photometry and Lightcurve of the Binary Potentially Hazardous Asteroid (285263) 1998 QE2 with Photometric Analysis Methods
Mentor:Michael Hicks, Astronomer, JPL/Caltech
Photometric observations of a near-Earth asteroid are used to produce a rotational lightcurve for the asteroid, as well as to determine the phase curve and physical constants that describe the asteroid’s behavior. On August 19, 1998, LINEAR at Lincoln Laboratory ETS in New Mexico discovered near-Earth asteroid (285263) 1998 QE2 (MPEC 1998-Q19). This asteroid made its closest approach of the 21st century on May 31, 2013 at a distance of 0.039 AU, and was identified by the Minor Planet Center as being a Potentially Hazardous Asteroid. We observed asteroid 1998 QE2 from Table Mountain Observatory’s 0.6-m telescope, and obtained broadband photometric data over a total of four nights from July 16-19, 2013. Long-slit CCD spectrograms of 1998 QE2 were obtained using the Palomar 5-m Hale Telescope on June 05, 2013 (ATel #5132). Both the photometric and spectral data analyses show that 1998 QE2 is a Ch-type asteroid (Bus taxonomy). It was also a radar target observed at Goldstone throughout June 2013 by the JPL Radar Team, where it was determined to have a moon. We attempted to correlate our photometric lightcurve of asteroid 1998 QE2 with the known presence of the secondary body, and determined the synodic period of 1998 QE2. Our R(1,1,𝛼) measurements for asteroid 1998 QE2 clearly follow the trend of a low albedo object, and the lightcurve amplitude increased as the solar phase angle increased. The photometry of near-Earth asteroids involves a systematic data reduction process using the Image Reduction and Analysis Facility Software for a large number of images of an asteroid taken during its apparition. My presentation will describe our methods for photometric research of asteroids and the production and analysis of asteroid lightcurves, and discuss the process involved with reducing photometric image data.