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

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.

10 pages, 1 figure, 1 table

References in corpus (5)

• The first WASP public data release
• Chemically peculiar stars and their temperature calibration
• Automated classification of Hipparcos unsolved variables
• Spots on Am stars
• A search for rapid pulsations among 9 luminous Ap stars

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• New Photometrically Variable Magnetic Chemically Peculiar Stars in the ASAS-3 Archive
• New and improved rotational periods of magnetic CP stars from ASAS-3, KELT and MASCARA data
• Photometric variability of the LAMOST sample of magnetic chemically peculiar stars as seen by TESS
• Torsional oscillations and observed rotational period variations in early-type stars
• A spectroscopic test of the rotational modulation origin of periodic \emph{Kepler} photometric variability of A-type stars
• HD 240121 - an ACV variable showing anti-phase variations of the B and V light curves
• New magnetic chemically peculiar stars and candidates in the ATLAS First Catalog of Variable Stars
• Search for stellar spots in field blue horizontal-branch stars
• An Investigation of Four Chemically Peculiar Stars with Photometric Periods below 12 Hours
• The search for roAp stars: null results and new candidates from Stroemgren-Crawford photometry
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• Chemically peculiar stars on the pre-main sequence
• A Kepler K2 view of subdwarf A-type stars
• A case study of ACV variables discovered in the Zwicky Transient Facility survey