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arXiv · 0712.1033

HR 710 (HD 15144): An ultra-Sr-rich, magnetic Ap star with a close companion

C. R. Cowley·S. Hubrig
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Abstract

The magnetic, chemically peculiar A-star HR 710 (HD 15144, ADS 1849A, AB Cet) has a close companion in a nearly circular orbit. Its 3-day period is unusually short for such stars. The system emits moderately hard x-rays, which likely come from a white dwarf secondary (ADS 1849Ab). The Sr II spectrum is very strong, and the resonance lines show similar core-nib structure to the stronger Ca K line. We place only loose constraints on a model. There are indications of a lower electron/gas pressure than expected from the star's parallax and brightness. Strong-line profiles and anomalous excitation/ionization indicate significant deviations from traditional models, fixed by Teff, log{g}, and abundances. Weak spectral-line profiles and wavelength shifts probably indicate abundance patches rather than the presence of a secondary (ADS 1849Ab) spectrum. Our UVES spectra are from only one epoch. Additional low-noise, high-resolution spectra are needed. We discuss the spectrum within the context of abundance stratification.

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C. R. Cowley, S. Hubrig. 2007-12-20. HR 710 (HD 15144): An ultra-Sr-rich, magnetic Ap star with a close companion. https://doi.org/10.1111/j.1365-2966.2007.12827.x

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