1991•The Astronomical JournalRequires access
The rotation period of Epsilon ERI from photometry of its starspots
Gary J. Frey, D. S. Hall, Phil Mattingly, S. P. Robb, J. E. Wood, K. W. Zeigler, Bruce S. Grim
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Abstract
BV photometry at six observatories in 1988/1989 and 1989/1990 shows variability resulting from five starspots which lived 1 or 2 months each, had rotation periods in the range P between 10.0d and 12.3d, and had amplitudes in the range 0.01 m - 0.03 m. From the range in P it was possible to estimate k greater than 0.20 +/- 0.05 for the differential rotation coefficient. Ca II K-line photometry, polarimetry, and earlier photometry reported in the literature has also shown variability with periodicities in the same 10 d -12 d range.