We present a second-order analytical expansion of null equatorial geodesics in the Kerr metric. The equations developed are applied to the study of light transit in compact binary systems. We show that the effects arising from path bending have a significant influence on the computed time delays, even at first order of approximation in the

An analysis of about 27 h of fast photometry of the cool ZZ Ceti white dwarf PG2303+243 reveals (1) the presence of many modes (as many as 22), some of them of low enough amplitude to have escaped previous detection, and (2) a short time scale (less than 10 d) drastic variation in amplitude. A preliminary identification of the modes observed in

IAUC 5634 available at Central Bureau for Astronomical Telegrams. IAUC 5634 available at Central Bureau for Astronomical Telegrams.

Consideration is given to the suppression of the radial and polar escape of magnetic flux in the form of toroidal flux tubes (flux rings) from low latitudes in the overshoot region below the solar convection zone through the combined action of the subadiabatic ambient stratification and the rotationally induced forces. It is shown that a flux ring

The observed emission-line ratios of the extended emission-line regions of Cen A and 3C 227 are compared with the theoretical results from photoionization models, assuming a power-law spectrum for the nuclear ionizing radiation. We show that a variation of the optical depth of the emitting gas can mimic a variation of the ionization parameter. Most