# Real light curves of FK Comae Berenices [SSA]

{To show that the observed light curves of FK Comae Berenices are interference of a nonstationary and a stationary light curve. These two “real” light curves follow the active longitude period $(P_{\mathrm{act}})$ and the rotation period $(P_{\mathrm{rot}})$ of FK Com.} {The recently formulated general model for the light curves of chromospherically active binary stars is applied to 14 years of standard Johnson $V$ photometry of FK Com. } {We determine a unique value, $P_{\mathrm{rot}}=2.3976 \pm 0.0018$ days, for the rotation period of FK Com. The observed light curves can be modelled as interference of two real light curves, $f_1(\phi_{\mathrm{act}})$ and $f_2(\phi_{\mathrm{rot}})$, which are nonstationary and stationary in the rotational frame of reference. The observed \flip ~events, where the activity abruptly shifts 180 degrees in longitude, are connected to the interaction of these two curves at rotational phases $\phi_{\mathrm{rot}}=0.0$ and 0.5.} {Our light curve model can remove the “veil” of interference from the observed light curve, and give unique solutions for the real light curves $f_1(\phi_{\mathrm{act}})$ and $f_2(\phi_{\mathrm{rot}})$. The magnetic field evolution in chromospherically active single and binary stars is probably connected to the presence or absence of nonstationary and stationary parts in their observed light curves.}

L. Jetsu
Fri, 30 Dec 16
41/64

Comments: 9 pages, 9 figures, submitted to Astronomy & Astrophysics