AAVSO: American Association of Variable Star Observers

CCD Photometry, Light Curve Deconvolution, Period Analysis, Kinematics, and Evolutionary Status of the HADS Variable V460 Andromedae

Volume 47 number 1 (2019)

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Kevin B. Alton
UnderOak and Desert Bloom Observatories, 70 Summit Avenue, Cedar Knolls, NJ 07927; kbalton@optonline.net
Kazimierz Stẹpień
Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland, kst@astrouw.edu.pl

Abstract

Multi-color (BVIc) CCD-derived photometric data were acquired from V460 And, an intrinsic variable classically defined as a High Amplitude delta Scuti (HADS) type system. Deconvolution of precise time-series light curve data was accomplished using discrete Fourier transformation and revealed a fundamental mode (f0) of oscillation at ~13.336 d–1 along with five other partial harmonics (2f0–6f0). No other statistically significant frequencies were resolved following successive pre-whitening of each residual signal. An assessment of potential period changes over time was performed using six new times-of-maximum light produced from the present study along with other values reported in the literature. These along with sparsely-sampled data collected during the ROTSE-I (1999), Catalina Sky (2005–2013), and SuperWASP (2004–2008) surveys indicate that no substantive change in the primary pulsation period or amplitude (V-mag) has likely occurred over the past 20 years. Recent photometric data from space telescopes have in some cases contradicted traditional classification schemes and clouded the differences between HADS- and SX Phe-like variables. Herein using accurate cosmic distances and proper motions from Gaia DR2, we attempted to exploit potential kinematic differences between established populations of HADS and SX Phe variable stars as an alternate approach for classification. Finally, an investigation with PARSEC models for generating stellar tracks and isochrones provided valuable insight into the evolutionary status and physical character of V460 And.