Abstract
In this work, we present a new method to determine the surface gravity of δ Sct stars. We used a refined Δv−ρ¯ relation and the stellar parallaxes or luminosities to determine their masses and radii. A comparison with the data obtained from the binary analysis, has shown that the values found by both methods are equivalent, within the uncertainties. Moreover, thanks to the refined relation, the uncertainties in log g are of the order of those usually estimated with high-resolution spectroscopy. Because of that, this new method to determine the surface gravity is an important step forward to break the degeneracy problem in the spectroscopic analysis.
Highlights
The pulsating spectrum of δ Sct stars is one of the most problematic to interpret, despite the large number of observed frequencies [7, 26]
In the work we present here, we describe in detail the methodology to find such separation in the periodogram and we refine the relation found in GH15
Despite the clear linear relation between the stellar density and the large separation observed in GH15, the uncertainties of coefficients in the relation are likely over-estimated in their weighted-least-square fitting procedure
Summary
The pulsating spectrum of δ Sct stars is one of the most problematic to interpret, despite the large number of observed frequencies [7, 26] This is because it is complicated to carry out a mode identification or find obvious patterns in their spectra, and because of the difficulties of the theoretical analysis, due to the rapid rotation of most of them. A recent work has found a relation between this periodicity, pattern or large separation and the mean density of the star [9, GH15] All these results are agree with theoretical predictions, both based on non-rotating models [29] and on 2D models using a non-perturbative approach [22, 27]. Based on the ∆ν-ρrelation, we found the radii and, the surface gravity
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