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arXiv · 2404.17707

Deneb is a Large Amplitude Polarimetric Variable

Daniel V. Cotton·Jeremy Bailey·Jean Perkins·Derek L. Buzasi·Ievgeniia Boiko
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Abstract

We write to report the discovery that Deneb is a large amplitude polarization variable. Over a ~400 d time span from August 2022 Deneb's polarization was typically around 3900 parts-per-million (ppm) in the SDSS g'-band. Yet, it varied by several hundred ppm in an irregular way on a timescale of weeks. The largest polarization change, amounting to 2500 ppm, occurred shortly after the last pulsation ``resumption'' event identified by Abt et al. (2023) in TESS photometry. The relationship between the observed polarization -- particularly corresponding to the resumption event -- and its brightness and H-alpha spectra suggests a mechanism involving density changes in its wind and/or extended atmosphere. Smaller effects due to pulsations are not ruled out and further study is recommended.

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Daniel V. Cotton, Jeremy Bailey, Jean Perkins, Derek L. Buzasi, Ievgeniia Boiko. 2024-04-26. Deneb is a Large Amplitude Polarimetric Variable. https://arxiv.org/abs/2404.17707

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