Physical properties of five near-Earth asteroids within the NEOROCKS project

ABSTRACT We present photometric data of five near-Earth asteroids (NEAs) obtained in the framework of the NEO Rapid Observation, Characterization, and Key Simulations (NEOROCKS) project. The selected asteroids are (351545) 2005 TE15, (438908) 2009 XO, (501647) 2014 SD224, 2015 FC35, and 2016 CO247. Light curves were obtained for all the asteroids using the 0.46-m TAR2 telescope at the Teide Observatory (OT), and spectrophotometric data in g, r, i, z$_s$ filters were obtained for asteroids (438908) 2009 XO and (501647) 2014 SD224 using the MuSCAT-2 instrument attached to the 1.52-m Carlos Sanchez Telescope also at the OT. We derived the rotational period of the five NEAs using Fourier series analysis of the rotational light curves. We found $P = 10.6035 \pm 0.0010$ h for (351545) 2005 TE15, $7.9140 \pm 0.006$ h for (501647) 2014 SD224, $3.4211 \pm 0.0075$ h for 2015 FC35, and $4.800 \pm 0.005$ h for 2016 CO247. We observed two periodic variations for (438908) 2009 XO, a long one with two possible periods of $P_1 = 157.2 \pm 0.4$ h and $P_2 = 304.0 \pm 0.4$ h and a large amplitude of 0.881 mag, and a short one with a period of $P = 13.448 \pm 0.008$ h. Radar data suggest that (438908) 2009 XO could be a contact binary and its double period points towards a non-principal axis rotator. Finally, we used the spectrophotometric data to obtain colours and taxonomic classification for (438908) 2009 XO and (501657) 2014 SD224, concluding that both NEAs are S-type objects.