Taxonomic classification of 80 near-Earth asteroids

The near-Earth objects are not only important for studying the early formation of the Solar System, but also pose a serious hazard to humanity since they can make close approaches to the Earth. The study of their physical properties can provide useful information on their origin, evolution and hazard to human being. However, it is still challenging to investigate the newly discovered small near-Earth objects because of their limited observational window. We aim to derive the visible colors of near-Earth asteroids and perform an initial taxonomic classification to analyze their relationship with size or orbital parameters. Observations were performed using the Yaoan High Precision Telescope and the 1.88m telescope at the Kottamia Astronomical Observatory in broadband BVRI Johnson-Cousins photometric system. We present new photometric observations for 84 near-earth asteroids, and taxonomical classification of 80 of them based on their photometric colors. Our results show that nearly half (46.3%) of the objects in our sample are classified as S-complex members, 26.3% as C-complex, 6% as D-complex and 15.0% as X-complex; the remaining belong to the A- or V-type. Additionally, we identified three P-type NEAs in our sample according to the Tholen scheme. The fractional abundances of the C/X-complex members with H ≥ 17.0 were more than twice as large as those with H < 17.0. However, the fractions of C- and S-complex members with D ≤ 1km and D > 1km remains nearly the same, while X-complex members tend to have sub-kilometer diameters. In our sample, the C/D-complex objects are predominant among those with a Jovian Tisserand parameter of TJ < 3.1. These bodies could have a cometary origin. C- and S-complex members account for a considerable proportion of potentially hazardous asteroids.