CCD PHOTOMETRY AND EVOLUTIONARY STATUS OF THE HADS VARIABLE PT COM

Abstract

Multi-color (BVIc) CCD-derived photometric data were acquired from PT Com, a pulsating variable classified as a high amplitude δ Scuti-type system. Analysis of precise time-series lightcurve data was accomplished using discrete Fourier transformation which revealed a mean fundamental mode (f0) of oscillation at 12.178364 ± 0.000083 d−1 along with at least three other partial harmonics (2f0, 3f0 and 4f0). No other statistically significant frequency shared by all bandpasses was resolved following successive pre-whitening of each residual signal. A secular analysis of the fundamental pulse period since 1999 was facilitated by the addition of 35 new times-of-maximum. The evolutionary status, age and physical nature of PT Com were investigated using the PAdova & TRieste Stellar Evolution Code for generating stellar tracks and isochrones.