AAVSO: American Association of Variable Star Observers

High Speed Photometry of V455 Andromedae With a Small Telescope (Abstract)

Volume 36 number 2 (2008)

Donald F. Collins

Abstract

(Abstract only) The recent eruption of V455 Andromedae to brighter than magnitude 11 has enabled unfiltered high speed photometry for this system. In mid-September 2007 the star was sufficiently bright that observations every thirteen seconds were acquired using a small telescope (20 cm SCT) and SBIG ST7 CCD camera. Fourier transform techniques detected a strong signal at 68 seconds-per-cycle on September 22–23, 2007 (JD 2454366.6) when the system brightness was about magnitude 12.5. Faint signals at 67 seconds were detected on earlier dates: September 18–19 (JD 2454362.6) and September 19–20, 2007 (JD 2454363.6). Fainter signals were also detected on later dates: September 28–29 (JD 2454372.6) at 71 seconds, and October 5-6 (JD 2454379.6) at 71 seconds. No isolated signals at the short 67–71 second periods were detected on other dates: JD 2454360.0, JD 2454381.6, and JD 2454388.6 (September 15–16, October 7-8, and October 14–15). When the 67–70 second signals were the strongest, the turbulence in the light curve was visibly weakest leading to a strong isolated short period signal. It is hypothesized that the short signal may be closely linked to the rotation period of the white dwarf at the core of the accretion disk. The large signal on one of the dates may indicate a temporary brightening of a hot spot on the surface of the white dwarf. Students Emily Woodall, Alex Pearce, Gordon Jones, and Ted Risberg assisted the observations and analysis. This study was supported by the American Astronomical Society Small Projects Grants Program.