Maureen L. Hintz

Photometric Abundance Calibration of δ Scuti Stars Using hk Photometry

The hk index has been used as a metallicity indicator for RR Lyrae variable stars. It is now being applied to the shorter period δ Scuti variables. Employing spectroscopic abundances of stars with published hk values and photometric indices calculated from stellar atmosphere models, a three-dimensional interpolation is used to determine [Fe/H] from intrinsic b-y, c1, and hk values. The resulting [Fe/H], log g, and Teff values for 10 δ Scuti stars are presented.

TIME-SERIES ENSEMBLE PHOTOMETRY OF SX PHOENICIS STARS. II. AE URSAE MAJORIS

We have examined the short period, double-mode variable star AE Ursae Majoris. Using time series ensemble photometry we have determined six new times of maximum light. We also applied a Fourier decomposition to the data to determine the component frequencies of the light curve. Using our data, along with archival data, we find that the period of AE UMa is continually decreasing at a rate of -1.14x 10-10 d d-1 . However, from the Fourier decomposition we find that the period ratio P1/P0 has remained constant at 0.773. We also find that AE UMa is incorrectly classified as a SX Phoenicis star.