ABSTRACT
Photometric observations of the near-Earth asteroid (31345) 1998 PG by Pravec et al. (2000) found a rotation period of 2.51620 h. Also found was a secondary period of 7.0035 h, or the double-period of 14.007 h, possibly indicating an additional body in the system. An extended campaign by the authors in 2018 lead to a similar primary period of 2.5168 h. However, instead of a 7-hour secondary period, one of about 16 hours was found with the lightcurve showing apparent mutual events (occultations and/or eclipses). The data sets from 1998 and 2018 could not be fit to a secondary period near the one found at the opposing apparition. The conclusion is that the asteroid is very likely binary, but - other than the primary rotation period - the system's parameters are ill-defined and only future observations will sufficiently refine them.
ABSTRACT
The near-Earth asteroid 2015 TB145 made a fly-by of Earth in 2015 October. We observed the NEA in support of radar observations planned for late October. Our data set of more than 1200 data points obtained from October 19-31 led to a solution of P = 2.938 ± 0.002 h and A = 0.13 ± 0.02 mag.
ABSTRACT
The near-Earth asteroid 2015 CN13 made a fly-by of Earth in late 2015 February. We observed the asteroid on Feb 25, 26, and 28. Analysis of the data set found two possible periods, the most likely being P = 22.7 ± 0.3 h. Given the estimated diameter of 70 meters and long period, this puts 2015 CN13 in a small group of NEAs with D ≤ 140 meters and periods well below the spin barrier, i.e., approximately P ≥ 2.2 hours.
