Real light curves of FK Comae Berenices: Farewell flip-flop

Research output: Contribution to journalArticleScientificpeer-review


For seven decades, the widely held view has been that the formation, the migration and the decay of short-lived starspots explain the observed constantly changing light curves of chromospherically active stars. We argue that these observed deceptive light curves are interference of two real constant period light curves of long-lived starspots. The slow motion of these long-lived starspots with respect to each other causes the observed light curve changes. In our first paper, we made six specific questions which undermine our argument. We could not answer all those questions, because we could not solve the real light curves of FK Com. Here, we formulate a period finding method that detects the two real light curves behind the observed light curve. Now we can answer all the above mentioned six specific questions. The long-lived structure predicted by our argumentis present in FK Com. The two periodicities of this structure are also present in its long-term mean light curves. Our argument explains many spurious phenomena: the observed rapid light curve changes, the short starspot life-times, the rapid rotation period changes, the active longitudes, the starspot migration, the period cycles, the amplitude cycles and the minimum epoch cycles. It also explains why the surface images and the light curves give contradicting surface differential rotation estimates even for the same individual star, as well as the abrupt 180 degrees shifts of activity (the flip-flop events) and the long-term mean light curves. We argue that the current views of starspots need to be revised.
Original languageOther/Unknown
JournalMonthly Notices of the Royal Astronomical Society
Publication statusUnpublished - 26 Jul 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • astro-ph.SR

Cite this