Large amplitude change in spot-induced rotational modulation of the Kepler Ap star KIC 2569073

Drury, Jason A. and Murphy, Simon J. and Derekas, Aliz and Sódor, Ádám and Stello, Dennis and Kuehn, Charles A. and Bedding, Timothy R. and Bognár, Zsófia and Szigeti, László and Szakáts, Róbert and Sárneczky, Krisztián and Molnár, László (2017) Large amplitude change in spot-induced rotational modulation of the Kepler Ap star KIC 2569073. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 471 (3). pp. 3193-3199. ISSN 0035-8711

Preview

Text 1707.05788.pdf - Accepted Version Download (3MB) | Preview

Abstract

An investigation of the 200 × 200 pixel 'superstamp' images of the centres of the open clusters NGC 6791 and NGC 6819 allows for the identification and study of many variable stars that were not included in the Kepler target list. KIC 2569073 (V=14.22), is a particularly interesting variable Ap star that we discovered in the NGC 6791 superstamp. With a rotational period of 14.67 days and 0.034-mag variability, it has one of the largest peak-to-peak variations of any known Ap star. Colour photometry reveals an anti-phase correlation between the B band, and the V, R and I bands. This Ap star is a rotational variable, also known as an α2 CVn, star, and is one of only a handful of Ap stars observed by Kepler. While no change in spot period or amplitude is observed within the 4-year Kepler timeseries, the amplitude shows a large increase compared to ground-based photometry obtained two decades ago.

Actions (login required)

Edit Item