CCD photometric observations of the near-Earth asteroid 2009 FG19 were made in 2014 September and October to supplement radar observations made at the same time. Analysis of the CCD data from September only found several possible periods, all commensurate with an Earth day. The most likely period was 8.
View Article and Find Full Text PDFAnalysis of CCD photometric observations of the near-Earth asteroid (399307) 1991 RJ2 made in 2014 August-September show it to be a binary system with a primary period of 3.4907 ± 0.0002 h and orbital period of 15.
View Article and Find Full Text PDFHitherto, rings have been found exclusively around the four giant planets in the Solar System. Rings are natural laboratories in which to study dynamical processes analogous to those that take place during the formation of planetary systems and galaxies. Their presence also tells us about the origin and evolution of the body they encircle.
View Article and Find Full Text PDFPairs of asteroids sharing similar heliocentric orbits, but not bound together, were found recently. Backward integrations of their orbits indicated that they separated gently with low relative velocities, but did not provide additional insight into their formation mechanism. A previously hypothesized rotational fission process may explain their formation-critical predictions are that the mass ratios are less than about 0.
View Article and Find Full Text PDFGamma-ray bursts (GRBs) and their afterglows are the most brilliant transient events in the Universe. Both the bursts themselves and their afterglows have been predicted to be visible out to redshifts of z approximately 20, and therefore to be powerful probes of the early Universe. The burst GRB 000131, at z = 4.
View Article and Find Full Text PDF