Characterizing and Developing a Shape Model for a Potentially Hazardous Asteroid.

This study entails the development of a 3-D shape model for potentially hazardous asteroid (PHA), 68950 2002QF15 (QF15), using the combination of ephemeris points, optical and near-infrared lightcurves and radar observations. Apollo class asteroid, QF15 was discovered on August 27th, 2002, by the LINEAR project at the Lincoln Laboratory experimental test site in Socorro, New Mexico. In 2019, the near-Earth asteroid (NEA) made its nearest approach to Earth at approximately 0.08825 astronomical units (AU). The Arecibo Observatory (AO) monitored the near-Earth flyby with the 305-meter (m) telescope using an S-band radar system (2830 MHz). The AO carried out 7 radar observations of QF15, spanning from May 20th, 2019 – June 5th, 2019. In addition, 15 optical lightcurve profiles, for QF15, were obtained by the Center of Solar System Studies-Palmer Divide Station (CS3-PDS), spanning several days between June 1st, 2019 - June 24th, 2019. Furthermore, many 24+ hour thermal infrared observations, for QF15, in the 3.4 and 4.6 microns (μm) infrared bands, produced by the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) from 2016 to 2019, were utilized during the QF15 shape model construction. The combination of multiple data sources is useful for refining the characteristics and developing a shape model for an asteroid. The continuous wave spectra and delay-Doppler profiles, produced from radar observations, provide information about the asteroid's approximate shape, and surface features. Additionally, the rotational period for an asteroid is estimated by analyzing the time intervals between peaks and cusps in the lightcurves. Moreover, evaluating the variations between the maxima and minima peaks in the lightcurve data is used for approximating the size of an asteroid.