Astron. Astrophys. Suppl. Ser. 140, 29-53

Starspot photometry with robotic telescopes. $UBV(RI)_{\rm C}$ and by light curves of 47 active stars in 1996/97

K.G. Strassmeier - E. Serkowitsch - Th. Granzer

Institut für Astronomie, Universität Wien, Türkenschanzstraße 17, A-1180 Wien, Austria
e-mail: strassmeier@astro.univie.ac.at, eddi@photon.phys.vuw.ac.nz, granzer@astro.univie.ac.at

Received March 15; accepted September 3, 1999

Abstract:

We present continuous multicolor photometry for 47 stars from October 1996 through June 1997. Altogether, 7073 $V(RI)_{\rm c}$, UBV, and by data points, each the average of three individual readings, were acquired with three automatic photoelectric telescopes (APTs) at Fairborn Observatory in southern Arizona. Most of our targets are chromospherically active single and binary stars of spectral type G to K but there are also four pre-main-sequence objects and three pulsating stars in our sample. The light variability is generally due to rotational modulation of an asymmetrically spotted stellar surface and therefore precise rotational periods and their seasonal variations are determined from Fourier analysis. We also report on photometric variations of $\gamma$ CrB (A0V) with a period of 0.44534 days. All data are available in numerical form.

Key words: stars: activity -- stars: late-type -- stars: rotation -- binaries: spectroscopic -- techniques: photometric