Microvariability and fast variability of stars. I. standard stars

Abstract

This is a study of observations of the photometric quantities Vt andBt, reported in the Hipparcos catalog, for 15 standard stars in order to search for microvariability and rapid variability in their emission. The microvariability is found to be characterized mainly by smooth fluctuations in the brightness. Changes in the magnitudes of the stars HD 28355 and HD 130109 with a period of ~150 min and an amplitude <0 m .02 appear to be caused by vertical shifts in their photospheres. Changes in the magnitudes with an amplitude of ~0 m .01 and a period of 11.4 d in the star e Eri were related to the rotation of spots. A similar microvariability period and amplitude in the star 51 Peg most likely originates in the influence of a planet.

Young stars in gas-dust disks. I. Fomalhaut

“…An approximate regression fit (sinusoid), y = f(ph), with an amplitude of 0 m .0169 is drawn through the points.As in Ref 27,. we have calculated the variance in the magnitudes from the regression curve and a correlation coefficient of 0.729 that indicates the strength of the coupling, the significance of which was determined with a confidence coefficient of >99.9%.…”