Rotational Modulation, Shear, and Cyclic Activity in HII 1883

Jacquelynne Brenda Milingo, Gettysburg College
S. H. Saar
Laurence A. Marschall, Gettysburg College
J. R. Stauffer, Spitzer Science Center


We present a 30 year compilation of V-band differential photometry for the Pleiades K dwarf HII 1883. HII 1883 has an average rotational period (Pr ot) of ~ 0.235d and displays rotational modulation due to non-uniform surface brightness as large as 0.2 magnitudes in V.Preliminary work yields a cycle period of ∼ 9yrs and rotational shear oPr ot/(Pr ot) considerably less than solar. With such a long baseline of data available we can explore many aspects of the star’s photometric variability. We present studies of the variation of the rotational modulation amplitude, (V), and Pr ot over the cycle.