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Study of FK Comae Berenices. II. Spot evolution from 1994 to 1997

H. Korhonen·S. V. Berdyugina·T. Hackman·K. G. Strassmeier·I. Tuominen
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Abstract

We present new surface (Doppler) images of the late-type single giant FK Com for June-July 1996, July-August 1996, April 1997 and June 1997. These images are compared with the previously published images from 1994 and 1995. The consecutive maps are cross-correlated to see the possible migration of the spots and the effects of differential rotation. The cross-correlation confirms an average longitudinal spot migration of 0.22+/-0.03 in phase within a year. This movement is probably an artifact caused by a difference between the accepted rotation period and the real photometric period for these years. If this is true, then the photometric rotation period for these years is 2.4037+/-0.0005 days. Measurements from these four years and six maps limit the surface differential rotation to alpha=0.0001+/-0.0002, where alpha is the difference between polar and equatorial angular velocities relative to the equatorial angular velocity.

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H. Korhonen, S. V. Berdyugina, T. Hackman, K. G. Strassmeier, I. Tuominen. 2000-07-07. Study of FK Comae Berenices. II. Spot evolution from 1994 to 1997. https://arxiv.org/abs/astro-ph/0007088

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