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 Sodor, Adam and Stello, Dennis and Kuehn, Charles A. and Bedding, Timothy R. and Bognar, Zsofia and Szigeti, Laszlo and Szakats, Robert and Sarneczky, Krisztian and Molnar, Laszlo (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

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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 d and 0.034 mag variability, it has one of the largest peak-to-peak variations of any known Ap star. Colour photometry reveals an antiphase 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 yr Kepler time series, the amplitude shows a large increase compared to ground-based photometry obtained two decades ago.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: File reproduced in accordance with the copyright policy of the publisher/author.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 28 Apr 2022 23:50
Last Modified: 16 May 2022 02:54
Uncontrolled Keywords: Stars: chemically peculiar; Stars: individual: KIC 2569073; Stars: rotation; Starspots; Techniques: photometric; Astrophysics - Solar and Stellar Astrophysics
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
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