AAS 198th Meeting, June 2001
Session 46. Variable and Binary Stars - Photometry
Display, Tuesday, June 5, 2001, 10:00am-6:30pm, Exhibit Hall

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[46.07] Crabs and Butterflies: Does WY Cancri Have Latitudinal Spot Migration Patterns?

P.A. Heckert (Western Carolina U.)

The short-period eclipsing RS CVn system, WY Cancri, displayed secular luminosity increases in 1988 (possibly 1986-88) and in 1997. On the basis of longitudinal spot migration reversals, Heckert (2001, AJ; 121, 1076) suggests that these luminosity increases signal the start of a new magnetic activity cycle. Are there associated latitudinal spot migration patterns? Keeping in mind that the latitude is the most difficult, and hence least reliable, spot parameter to model, I examine the modeled spot latitudes from 1988 to 2001 to address this question. Plotting latitude vs. year shows that the highest latitude spots occurred in 1990 and 2000, a few years after the luminosity increases and longitudinal migration reversals noted above. The spot latitudes then tend to decrease with time. With the caveats that spot latitudes are difficult to model and that it takes several cycles to demonstrate cyclic behavior, this plot is reminiscent of the solar butterfly diagram. With the present data, it appears that active regions occur at maximum latitudes a few years after the secular luminosity increases then migrate to lower latitudes. I examine plots both with and without sorting the spots by active longitude belts. Continued observations are needed to test this trend.

I acknowledge generous amounts of observing time at Mt. Laguna Observatory over many years. I also acknowledge support from the Cottrel College Science Program of the Research Corporation, the AAS small grants program, and Western Carolina University.

The author(s) of this abstract have provided an email address for comments about the abstract: heckert@wcu.edu

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