preprint submitted J. Vandersnickt author R. Ochoa Armenta author V. Vanlaer author A. David-Uraz A. David-Uraz author C. Aerts author S. B. Das author J. -C. Bouret author D. M. Bowman author Lisa Annabelle Bugnet author d9edb345-f866-11ec-9b37-d119b52345010000-0003-0142-4000 V. Khalack author J. Labadie-Bartz J. Labadie-Bartz author S. Mathis author Y. Nazé author C. Neiner author P. Petit author V. Petit author K. Thomson-Paressant K. Thomson-Paressant author T. Van Doorsselaere author M. Vanrespaille author LiBu department The polarization of light is a critically under-utilized, rich source of information in astronomy. For stars in particular, surface magnetism polarization that can be detected and measured with spectro-polarimetry. Many questions about these surface fields remain unanswered due to a lack of dedicated instruments capable of probing weak and strong surface magnetic fields for the entire mass range of stars, from M-dwarfs (and even substellar objects) to massive O-type stars at different evolutionary stages and metallicities. These questions range from the origin of these fields to their true incidence rate throughout the stellar population and the dependence on metallicity. Magnetic fields, although currently often excluded from stellar evolution models, play an important role in stellar evolution. Connecting the surface fields to internal fields through asteroseismology will instigate a new era of understanding stellar evolution and the transport of angular momentum and chemical elements throughout stellar interiors, also impacting our understanding of star-planet interactions and stellar remnants. Polarimetry is also an under-utilized tool to observationally constrain the mode identification of nonradial oscillations, which lies at the basis of accurate asteroseismic parameter estimation at percentage-level for stellar radii, masses, ages, internal rotation, and magnetic field strengths. Combining strong constraints on mode identification and surface magnetic properties through the acquisition of time-resolved, high-resolution and high-signal-to-noise (S/N) spectro-polarimetry and spectroscopy promises to bring leaps forward in our understanding of stellar structure, particularly when combined with long-term space photometric data from past, current, and future missions. 2025 eng 2512.1517010.48550/arXiv.2512.15170 Vandersnickt, J., et al. “Expanding Stellar Horizons with Polarized Light.” <i>ArXiv</i>, 2512.15170, doi:<a href="https://doi.org/10.48550/arXiv.2512.15170">10.48550/arXiv.2512.15170</a>. J. Vandersnickt, R.O. Armenta, V. Vanlaer, A.D.-U. A. David-Uraz, C. Aerts, S.B. Das, J.-C. Bouret, D.M. Bowman, L.A. Bugnet, V. Khalack, J.L.-B. J. Labadie-Bartz, S. Mathis, Y. Nazé, C. Neiner, P. Petit, V. Petit, K.T.-P. K. Thomson-Paressant, T.V. Doorsselaere, M. Vanrespaille, ArXiv (n.d.). Vandersnickt, J., Armenta, R. O., Vanlaer, V., A. David-Uraz, A. D.-U., Aerts, C., Das, S. B., … Vanrespaille, M. (n.d.). Expanding stellar horizons with polarized light. <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.2512.15170">https://doi.org/10.48550/arXiv.2512.15170</a> Vandersnickt, J., R. Ochoa Armenta, V. Vanlaer, A. David-Uraz A. David-Uraz, C. Aerts, S. B. Das, J. -C. Bouret, et al. “Expanding Stellar Horizons with Polarized Light.” <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.2512.15170">https://doi.org/10.48550/arXiv.2512.15170</a>. J. Vandersnickt <i>et al.</i>, “Expanding stellar horizons with polarized light,” <i>arXiv</i>. . Vandersnickt J, Armenta RO, Vanlaer V, A. David-Uraz AD-U, Aerts C, Das SB, Bouret J-C, Bowman DM, Bugnet LA, Khalack V, J. Labadie-Bartz JL-B, Mathis S, Nazé Y, Neiner C, Petit P, Petit V, K. Thomson-Paressant KT-P, Doorsselaere TV, Vanrespaille M. Expanding stellar horizons with polarized light. arXiv, 2512.15170. Vandersnickt J, Armenta RO, Vanlaer V, et al. Expanding stellar horizons with polarized light. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.2512.15170">10.48550/arXiv.2512.15170</a> 213092026-02-17T13:53:50Z2026-04-07T06:00:40Z