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Paper: Fundamental Parameters of the sdB Pulsator PG 1219+534: The Importance of High Sensitivity Observations for Detailed Asteroseismology of EC14026 Stars
Volume: 334, 14th European Workshop on White Dwarfs
Page: 615
Authors: Charpinet, S.; Fontaine, G.; Brassard, P.; Green, E.M.; Chayer, P.
Abstract: We report on detailed analyses of high sensitivity spectroscopy and white light fast photometry of the rapid hot B subdwarf (sdB) pulsator – or EC14026 star – PG 1219+534. These complementary studies – i.e., quantitative spectroscopy and detailed asteroseismology – allow for the determination of the fundamental parameters of that star. The primary derived quantities are 1) the surface gravity, 2) the effective temperature, 3) the total mass, and 4) the mass of the outer H-rich envelope. Secondary quantities are 1) the radius, 2) the luminosity, 3) the absolute visual magnitude, 4) the distance, 5) a limit on the rotation period, and 6) a limit on the equatorial rotation velocity. We also emphasize that for sdB pulsators with simple enough period spectra (such as PG 1219+534), high S/N ratio is more important than time coverage (although, of course, best is to have both) for the goal of asteroseismology. Mixing low-quality and high S/N ratio light curves just ruins all the benefit of the high S/N data, as the noise level in the Fourier domain is essentially set by the lowest quality light curve. This has implications in the context of multisite campaigns mixing heterogeneous data sets. This also strengthens our conviction that future observational improvements for detailed asteroseismology of EC14026 stars resides in short bi- (or tri-) site campaigns involving 4m-class telescopes with the aim of gathering more homogeneous high-sensitivity data. This would be in addition to recent efforts to perform multicolor fast-photometry and time resolved spectroscopy on these pulsating stars.
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