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| Main Authors: | , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.11672 |
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| _version_ | 1866912587507040256 |
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| author | Power, Michael T. Neilson, Hilding R. Sherren, Galina |
| author_facet | Power, Michael T. Neilson, Hilding R. Sherren, Galina |
| contents | Decades of observations on the star V Canum Venaticorum (V CVn) have revealed an unusual inverse relationship between its linear polarization and light curves (sometimes with a lead/lag time between them) and an almost constant polarization position angle. One theory proposed to explain this behaviour is the existence of a bow shock driven by a spherically symmetric time-varying dusty wind from the star, which is assumed to vary due to radial pulsations. To test this hypothesis, this study uses a new framework developed in \textsc{ZEUS3D}, a multiphysics magnetohydrodynamics code. The results of this work show that when a time-varying stellar wind is at its maximum brightness, the polarization signal is at a minimum due to the wind structure and a dense, symmetric shell that forms around the star. Conversely, when the brightness is at a minimum, the symmetric shell around the star is much less dense, and the polarization is instead dominated by the asymmetric bow shock structure, causing the polarization signal to attain a maximum value. Numerically reproducing the observed inverse relationship between the polarization and light curve provides a strong theoretical argument that a variable stellar wind bow shock is the solution to the curious case of V CVn. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_11672 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The Curious Case of V CVn Power, Michael T. Neilson, Hilding R. Sherren, Galina Solar and Stellar Astrophysics Decades of observations on the star V Canum Venaticorum (V CVn) have revealed an unusual inverse relationship between its linear polarization and light curves (sometimes with a lead/lag time between them) and an almost constant polarization position angle. One theory proposed to explain this behaviour is the existence of a bow shock driven by a spherically symmetric time-varying dusty wind from the star, which is assumed to vary due to radial pulsations. To test this hypothesis, this study uses a new framework developed in \textsc{ZEUS3D}, a multiphysics magnetohydrodynamics code. The results of this work show that when a time-varying stellar wind is at its maximum brightness, the polarization signal is at a minimum due to the wind structure and a dense, symmetric shell that forms around the star. Conversely, when the brightness is at a minimum, the symmetric shell around the star is much less dense, and the polarization is instead dominated by the asymmetric bow shock structure, causing the polarization signal to attain a maximum value. Numerically reproducing the observed inverse relationship between the polarization and light curve provides a strong theoretical argument that a variable stellar wind bow shock is the solution to the curious case of V CVn. |
| title | The Curious Case of V CVn |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2509.11672 |