RESUMO
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.
RESUMO
Observations of three near-Earth asteroids (NEAs) were made between 1993 and 2016. The resulting data were used to find preliminary pole and shape models for 1863 Antinous, (5836) 1993 MF, and (154244) 2002 KL6.
RESUMO
A collaboration of two observers at widely-separated longitudes made CCD photometric observations of the near-Earth asteroid (NEA) 1943 Anteros from 2016 August to October. Analysis of the data led to the possibility that the asteroid is a binary with P 1 = 2.86923 ± 0.00006 h, A 1 = 0.07 mag and P ORB = 23.548 ± 0.002 h, A 2 = 0.05-0.10 mag. The estimated effective diameter ratio is Ds/Dp ≥ 0.22 ± 0.02.
RESUMO
Analysis of CCD photometric observations of near-Earth asteroid (154244) 2002 KL6 indicate that it may be a binary system. The presumed primary has a synodic rotation period of 4.60869 ± 0.00005 h and lightcurve amplitude of 0.65 ± 0.03 mag. The presumed satellite has an orbital period of 24.05 ± 0.02 h and maximum lightcurve amplitude of 0.07 mag. The secondary lightcurve showed no mutual events and seems to indicate that the satellite's rotation is tidally locked to its orbital period.
RESUMO
Analysis of CCD photometric observations of the near-Earth asteroid (331471) 1984 QY1 show that it is likely in non-principal axis rotation (NPAR), or tumbling. A single period analysis found a dominant period of 45.5 ± 0.5 h, but the true periods of rotation and precession could not be determined.
RESUMO
Initial CCD photometry observations of the Hungaria asteroid 5426 Sharp in 2014 December and 2015 January at the Center of Solar System Studies-Palmer Divide Station in Landers, CA, showed attenuations from the general lightcurve, indicating the possibility of the asteroid being a binary system. The secondary period was almost exactly an Earth day, prompting a collaboration to be formed with observers in Europe, which eventually allowed establishing two periods: P1 = 4.5609 ± 0.0003 h, A1 = 0.18 ± 0.01 mag and P2 = 24.22 ± 0.02 h, A2 = 0.08 ± 0.01 mag. No mutual events, i.e., occultations and/or eclipses, were seen, therefore the asteroid is considered a probable and not confirmed binary.
RESUMO
CCD photometry observations of the near-Earth asteroid (NEA) 2010 TN 54 indicates a period of either 6.14 h or 12.12 h, depending on whether a monomodal or bimodal lightcurve is adopted. The amplitude was only 0.07 ± 0.01 mag, which - along with the period being nearly commensurate with an Earth day - made finding a definitive solution difficult, despite being observed from locations in North America and Europe.
RESUMO
Analysis of CCD photometry observations of the near-Earth asteroid (162566) 2000 RJ34 indicates a period of 50.5 ± 0.1 h. The amplitude was 0.78 ± 0.03 mag. The long period nearly commensurate with an Earth day made it critical that at least two stations, well-separated in longitude, be involved in the observing campaign.
