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arXiv · 2404.01420

Variations in Line Profiles of Atomic Transitions in RR Lyrae Stars

Christopher Sneden·George W. Preston
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Abstract

We have investigated the absorption shapes of atomic lines and H{\alpha} in RR Lyrae stars. We used the database of high resolution spectra gathered with the Las Campanas Observatory du Pont Telescope, analyzing a set of about 2700 short exposure spectra of 17 RRab and 5 RRc variables. To increase the signal-to-noise of the spectra for each star, we first co-added spectra in small photometric phase bins, and then co-added metallic line profiles in velocity space. The resulting line absorption shapes vary with photometric phase in a consistent manner for all RRab stars, while exhibiting no obvious phase-related variations for the RRc stars. We interpret these line profile variations in terms of velocity gradients in the photospheric layers that produce absorption line profiles. The H{\alpha} profiles are much broader, indicative of shock temperatures of order 100,000 K.

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Christopher Sneden, George W. Preston. 2024-04-01. Variations in Line Profiles of Atomic Transitions in RR Lyrae Stars. https://arxiv.org/abs/2404.01420

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