Abstract

No. The eclipsing binary light curve of $$\delta$$ Cap shows unexpectedly large scatter which in the past has been assumed to be due to a $$\delta$$ Scuti-like variation. However, an analysis of the published photometry finds no evidence to support a short-period variation in this system. The upper limit of any periodic variation is $$<0.008$$ mag in B and $$<0.007$$ mag in V. The dominant cause of the observed scatter in the photometry is most probably a combination of random noise and instrumental differences between observers. Although there is no direct evidence to support it, there is a possibility that spots on the active secondary contribute to the scatter in the broadband photometry. Phase-dependent Hα variations may require an explanation, and material held in magnetic loops or plages on the secondary are likely candidates. Reports of the period being variable are found to be misplaced. $$\delta$$ Cap is probably a constant metallic-lined A star with a mildly chromospherically active cool companion.