Precise surface gravities of $\delta$ Scuti stars from asteroseismology

Abstract

The work reported here demonstrates that it is possible to accurately determine surface gravities of $\delta$ Sct stars using the frequency content from high precision photometry and a measurement of the parallax. Using a sample of 10 eclipsing binary systems with a $\delta$ Sct component and the unique $\delta$ Sct star discovered with a transiting planet, WASP-33, we were able to refine the $\Delta \nu -\bar{\rho }$ relation. Using this relation and parallaxes, we obtained independent values for the masses and radii, allowing us to calculate the surface gravities without any constraints from spectroscopic or binary analysis. A remarkably good agreement was found between our results and those published, extracted from the analysis of the radial velocities and light curves of the systems. This reinforces the potential of $\Delta \nu$ as a valuable observable for $\delta$ Sct stars and settles the degeneracy problem for the $\log g$ determination through spectroscopy.

5 pages, 2 figures, 1 table

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• Study of rotational splittings in $\delta$~Scuti stars using pattern finding techniques
• Exploring the convective core of the hybrid $\delta$ Scuti-$\gamma$ Doradus star CoRoT 100866999 with asteroseismology
• An observer's view on the future of asteroseismology
• Pulsation and Rotation of the EL CVn-type Eclipsing Binary 1SWASP J024743.37-251549.2