Magnetic, chemically peculiar (CP2) stars in the SuperWASP survey

TL;DR

This study analyzed nearly 3.85 million photometric measurements from the SuperWASP survey to identify and characterize new magnetic chemically peculiar (CP2) stars exhibiting rotational variability, significantly expanding the known sample of ACV variables.

Contribution

It is the first large-scale survey to detect and report 74 new ACV variable stars among CP2 stars using extensive photometric data.

Findings

Identified 80 ACV variables, 74 of which are newly reported.

Established variability for 23 stars previously considered constant.

Provided light curve parameters for all detected variables.

Abstract

The magnetic chemically peculiar (CP2) stars of the upper main sequence are well-suited for investigating the impact of magnetic fields on the surface layers of stars, which leads to abundance inhomogeneities (spots) resulting in photometric variability. The light changes are explained in terms of the oblique rotator model; the derived photometric periods thus correlate with the rotational periods of the stars. CP2 stars exhibiting this kind of variability are classified as alpha2 Canum Venaticorum (ACV) variables. We have analysed around 3 850 000 individual photometric WASP measurements of magnetic chemically peculiar (CP2) stars and candidates selected from the Catalogue of Ap, HgMn, and Am stars, with the ultimate goal of detecting new ACV variables. In total, we found 80 variables, from which 74 are reported here for the first time. The data allowed us to establish variability for 23 stars which had been reported as probably constant in the literature before. Light curve parameters were obtained for all stars by a least-squares fit with the fundamental sine wave and its first harmonic. Because of the scarcity of Stroemgren uvbybeta measurements and the lack of parallax measurements with an accuracy better than 20%, we are not able to give reliable astrophysical parameters for the investigated objects.