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Session 67 - Stars: Evolution, Atmospheres, Intrinsic.
Display session, Thursday, June 11
Atlas Ballroom,
We report on differential Strömgrenn photometry of several B and A stars made with the 0.75-m Four College Automated Photoelectric Telescope now at Washington Camp, AZ during The Citadel's share of observing time.
Our first observations of Deneb (A2 Iae) with approximately 20 observations during a time span of 50 days in the fall of 1997 show that the uvby values are approximately in phase and the variability cannot be described by variation with a single frequency. The range is about 0.06 magnitudes in each filter.
Our monitoring of the Be star \theta CrB (= HD 138749) and the cool magnetic Chemically Peculiar star HR 8216 (= HD 204411) show that these stars remained constant during the 1996/1997 and 1997/1998 observing seasons. Our photometry of the magnetic Chemically Peculiar star HD 50169 indicates it is not a photometric variable. We have found a new period for the magnetic Chemically Peculiar star HR 7786 (= HD 193722) of 8.5297 days.
We have confirmed Gulliver et al.'s (1985, AJ, 90, 1334) result that the photometric variability of the elliptical variable 33 Tau ( = HD 24769) occurs in Hube's (1981, AJ, 86, 1394) orbital period of 2.875272 days and reduced the error in the period.
We have used photometry made with the Hipparcos satellite to check that our comparison and check stars are sufficiently constant. A few such stars needed to be replaced as they were more variable than the stars whose constancy was being checked. Such star generally have standard errors of 0.005 mag and amplitudes of 0.02 mag.
This work was supported in part by NSF grant AST-9528506.
