Abstract
Magnetic fields are important for stellar photospheres and magnetospheres, influencing photospheric physics and sculpting stellar winds. Observations of stellar magnetic fields are typically made in the visible, although infrared observations are becoming common. Here we consider the possibility of directly detecting magnetic fields at ultraviolet (UV) wavelengths using high resolution spectropolarimetry, specifically considering the capabilities of the proposed Polstar mission. UV observations are particularly advantageous for studying wind resonance lines not available in the visible, but they can also provide many photospheric lines in hot stars. Detecting photospheric magnetic fields using the Zeeman effect and Least Squares Deconvolution is potentially more effective in the UV due to the much higher density of strong lines. We investigate detecting magnetic fields in the magnetosphere of a star using the Zeeman effect in wind lines, and find that this could be detectable at high S/N in an O or B star with a strong magnetic field. We consider detecting magnetic fields using the Hanle effect in linear polarization, which is complementary to the Zeeman effect, and could be more sensitive in photospheric lines of rapid rotators. The Hanle effect can also be used to infer circumstellar magnetism in winds. Detecting the Hanle effect requires UV observations, and a multi-line approach is key for inferring magnetic field properties. This demonstrates that high resolution spectropolarimetry in the UV, and the proposed Polstar mission, has the potential to greatly expand our ability to detect and characterize magnetic fields in and around hot stars.
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Data Availability
The UV-ADM code and model grid used for this work is available from author C. Erba upon request. The Least Squares Deconvolution code used is available at https://github.com/folsomcp/LSDpy. Other data used are available from the corresponding author on reasonable request.
Notes
Following Erba et al. (2021a), the models reported here use the Analytic Dynamical Magnetosphere (ADM) formalism (Owocki et al. 2016) to calculate the density and velocity structure of the magnetosphere. However, a snapshot of a 3D magnetohydrodynamic (MHD) simulation of the magnetosphere could also be used, which will be discussed in greater detail in a forthcoming paper.
The viewing angle \(\alpha \) is defined to be the angle between the line-of-sight to the observer and the north magnetic pole (Erba et al. 2021a).
References
Bianda, M., Stenflo, J.O., Solanki, S.K.: Hanle diagnostics of solar magnetic fields: the SR II 4078 Angstrom line. Astron. Astrophys. 337, 565–578 (1998)
Blazère, A., Petit, P., Lignières, F., et al.: Detection of ultra-weak magnetic fields in Am stars: \(\beta\) Ursae Majoris and \(\theta\) Leonis. Astron. Astrophys. 586, A97 (2016). https://doi.org/10.1051/0004-6361/201527556. 1601.01829 [astro-ph.SR]
Bommier, V.: Hanle effect from a dipolar magnetic structure: the case of the solar corona and the case of a star. Astron. Astrophys. 539, A122 (2012). https://doi.org/10.1051/0004-6361/201118245
Bommier, V., Sahal-Brechot, S.: The Hanle effect of the coronal L-alpha line of hydrogen – theoretical investigation. Sol. Phys. 78(1), 157–178 (1982). https://doi.org/10.1007/BF00151151
Bommier, V., Landi Degl’Innocenti, E., Leroy, J.L., et al.: Complete determination of the magnetic field vector and of the electron density in 14 prominences from linear polarizaton measurements in the HeI D3 and H\(\alpha\) lines. Sol. Phys. 154(2), 231–260 (1994). https://doi.org/10.1007/BF00681098
Bommier, V., Leroy, J.L., Sahal-Bréchot, S.: 24 synoptic maps of average magnetic field in 296 prominences measured by the Hanle effect during the ascending phase of solar cycle 21. Astron. Astrophys. 647, A60 (2021). https://doi.org/10.1051/0004-6361/202038868. 2007.08219 [astro-ph.SR]
Casini, R.: The Hanle effect of the two-level atom in the weak-field approximation. Astrophys. J. 568(2), 1056–1065 (2002). https://doi.org/10.1086/338986
Casini, R., Landi Degl’Innocenti, E.: Astrophysical plasmas. In: Fujimoto, T., Iwamae, A. (eds.) Plasma Polarization Spectroscopy, vol. 44. p 247 (2008). https://doi.org/10.1007/978-3-540-73587-8_12
Casini, R., López Ariste, A., Tomczyk, S., et al.: Magnetic maps of prominences from full Stokes analysis of the He I D3 line. Astrophys. J. Lett. 598(1), L67–L70 (2003). https://doi.org/10.1086/380496
David-Uraz, A., Erba, C., Petit, V., et al.: Extreme resonance line profile variations in the ultraviolet spectra of NGC 1624-2: probing the giant magnetosphere of the most strongly magnetized known O-type star. Mon. Not. R. Astron. Soc. 483(2), 2814–2824 (2019). https://doi.org/10.1093/mnras/sty3227. 1811.10113 [astro-ph.SR]
David-Uraz, A., Petit, V., Shultz, M.E., et al.: New observations of NGC 1624-2 reveal a complex magnetospheric structure and underlying surface magnetic geometry. Mon. Not. R. Astron. Soc. 501(2), 2677–2687 (2021). https://doi.org/10.1093/mnras/staa3768. 2010.07482 [astro-ph.SR]
del Pino Alemán, T., Casini, R., Manso Sainz, R.: Magnetic diagnostics of the solar chromosphere with the Mg II h-k lines. Astrophys. J. Lett. 830(2), L24 (2016). https://doi.org/10.3847/2041-8205/830/2/L24. 1607.05683 [astro-ph.SR]
del Pino Alemán, T., Trujillo Bueno, J., Štěpán, J., et al.: A novel investigation of the small-scale magnetic activity of the quiet sun via the Hanle effect in the Sr I 4607 Å line. Astrophys. J. 863(2), 164 (2018). https://doi.org/10.3847/1538-4357/aaceab. 1806.07293 [astro-ph.SR]
Donati, J.F.: ESPaDOnS: an echelle SpectroPolarimetric device for the observation of stars at CFHT. In: Trujillo-Bueno, J., Sanchez Almeida, J. (eds.) Solar Polarization, p. 41 (2003)
Donati, J.F., Brown, S.F.: Zeeman-Doppler imaging of active stars. V. Sensitivity of maximum entropy magnetic maps to field orientation. Astron. Astrophys. 326, 1135–1142 (1997)
Donati, J.F., Landstreet, J.D.: Magnetic fields of nondegenerate stars. Annu. Rev. Astron. Astrophys. 47(1), 333–370 (2009). https://doi.org/10.1146/annurev-astro-082708-101833. 0904.1938 [astro-ph.SR]
Donati, J.F., Semel, M., Carter, B.D., et al.: Spectropolarimetric observations of active stars. Mon. Not. R. Astron. Soc. 291(4), 658–682 (1997). https://doi.org/10.1093/mnras/291.4.658
Donati, J.F., Howarth, I.D., Jardine, M.M., et al.: The surprising magnetic topology of \(\tau\) Sco: fossil remnant or dynamo output? Mon. Not. R. Astron. Soc. 370(2), 629–644 (2006). https://doi.org/10.1111/j.1365-2966.2006.10558.x. astro-ph/0606156 [astro-ph]
Donati, J.F., Kouach, D., Moutou, C., et al.: SPIRou: NIR velocimetry and spectropolarimetry at the CFHT. Mon. Not. R. Astron. Soc. 498(4), 5684–5703 (2020). https://doi.org/10.1093/mnras/staa2569. 2008.08949 [astro-ph.IM]
Erba, C., David-Uraz, A., Petit, V., et al.: Ultraviolet line profiles of slowly rotating massive star winds using the ‘analytic dynamical magnetosphere’ formalism. Mon. Not. R. Astron. Soc. 506(4), 5373–5388 (2021a). https://doi.org/10.1093/mnras/stab1853. 2106.13676 [astro-ph.SR]
Erba, C., Shultz, M.E., Petit, V., et al.: Confirmation of \(\xi\)1 CMa’s ultra-slow rotation: magnetic polarity reversal and a dramatic change in magnetospheric UV emission lines. Mon. Not. R. Astron. Soc. 506(2), 2296–2308 (2021b). https://doi.org/10.1093/mnras/stab1454. 2105.08192 [astro-ph.SR]
Faurobert-Scholl, M.: Hanle effect of magnetic canopies in the solar chromosphere. Astron. Astrophys. 285, 655–662 (1994)
Ferrari, M., Bouret, J.C., Neiner, C., et al.: POLLUX, an innovative instrument providing a unique UV spectropolarimetric capability to LUVOIR. In: American Astronomical Society Meeting Abstracts, vol. 233, p. 148.09 (2019)
Fineschi, S., Hoover, R.B., Fontenla, J.M., et al.: Polarimetry of extreme ultraviolet lines in solar astronomy. Opt. Eng. 30, 1161–1168 (1991). https://doi.org/10.1117/12.55922
Folsom, C.P.: Explaining the unusual Stokes V signatures of ultra-weak magnetic A stars. Contrib. Astronom. Obs. Skalnate Pleso 48(1), 53–57 (2018)
Gayley, K.G.: The antiderivative of the Stokes V polarization profile. I. A simple procedure for magnetic field characterization. Astrophys. J. 851(2), 113 (2017). https://doi.org/10.3847/1538-4357/aa96b1
Gayley, K.G., Ignace, R.: The Zeeman effect in the Sobolev approximation: split monopole fields and the “heartbeat” Stokes V profile. Astrophys. J. 708(1), 615–624 (2010). https://doi.org/10.1088/0004-637X/708/1/615. 0906.3048 [astro-ph.SR]
Gayley, K.G., Owocki, S.P.: A simple mean-field diagnostic from Stokes V spectra. In: Meynet, G., Georgy, C., Groh, J., et al. (eds.) New Windows on Massive Stars, pp. 375–376 (2015). https://doi.org/10.1017/S1743921314007145
Grossmann-Doerth, U., Schuessler, M., Solanki, S.K.: Stokes V asymmetry and shift of spectral lines. Astron. Astrophys. 221(2), 338–341 (1989)
Grunhut, J.H., Wade, G.A., Folsom, C.P., et al.: The magnetic field and magnetosphere of Plaskett’s star: a fundamental shift in our understanding of the system. Mon. Not. R. Astron. Soc. (2021). https://doi.org/10.1093/mnras/stab3320. 2111.06251 [astro-ph.SR]
Hennicker, L., Puls, J., Kee, N.D., et al.: 3D radiative transfer: continuum and line scattering in non-spherical winds from OB stars. Astron. Astrophys. 616, A140 (2018). https://doi.org/10.1051/0004-6361/201731858. 1806.08155 [astro-ph.SR]
Ignace, R.: A re-evaluation of profile shapes from resonance line scattering in spherical stellar winds. Astron. Astrophys. 332, 686–694 (1998a)
Ignace, R.: Emission line profile shapes from anisotropic resonance line scattering in planar equatorial disks. Astron. Astrophys. 337, 819–831 (1998b)
Ignace, R.: Resonance line scattering polarization in optically thin planar equatorial disks. Astron. Astrophys. 363, 1106–1114 (2000)
Ignace, R., Cassinelli, J.P., Bjorkman, J.E.: Equatorial wind compression effects across the H-R diagram. Astrophys. J. 459, 671 (1996). https://doi.org/10.1086/176932
Ignace, R., Nordsieck, K.H., Cassinelli, J.P.: The Hanle effect as a diagnostic of magnetic fields in stellar envelopes. I. Theoretical results for integrated line profiles. Astrophys. J. 486(1), 550–570 (1997). https://doi.org/10.1086/304512
Ignace, R., Cassinelli, J.P., Bjorkman, J.E.: “WCFields”: a magnetic rotating stellar wind model from wind compression theory. Astrophys. J. 505(2), 910–920 (1998). https://doi.org/10.1086/306189
Ignace, R., Cassinelli, J.P., Nordsieck, K.H.: The Hanle effect as a diagnostic of magnetic fields in stellar envelopes. II. Some theoretical results for resolved line profiles. Astrophys. J. 520(1), 335–346 (1999). https://doi.org/10.1086/307435
Ignace, R., Nordsieck, K.H., Cassinelli, J.P.: The Hanle effect as a diagnostic of magnetic fields in stellar envelopes. IV. Application to polarized P cygni wind lines. Astrophys. J. 609(2), 1018–1034 (2004). https://doi.org/10.1086/421258. astro-ph/0403416 [astro-ph]
Ignace, R., Hole, K.T., Cassinelli, J.P., et al.: Time-dependent behavior of linear polarization in unresolved photospheres, with applications for the Hanle effect. Astron. Astrophys. 530, A82 (2011). https://doi.org/10.1051/0004-6361/201016292. 1103.4155 [astro-ph.IM]
Khan, A., Belluzzi, L., Landi Degl’Innocenti, E., et al.: Spectropolarimetric forward modelling of the lines of the Lyman-series using a self-consistent, global, solar coronal model. Astron. Astrophys. 529, A12 (2011). https://doi.org/10.1051/0004-6361/201015551
Kochukhov, O.: Diagnostic of stellar magnetic fields with cumulative circular polarisation profiles. Astron. Astrophys. 580, A39 (2015). https://doi.org/10.1051/0004-6361/201526318. 1505.07266 [astro-ph.SR]
Kochukhov, O., Piskunov, N., Ilyin, I., et al.: Doppler imaging of stellar magnetic fields. III. Abundance distribution and magnetic field geometry of alpha 2 CVn. Astron. Astrophys. 389, 420–438 (2002). https://doi.org/10.1051/0004-6361:20020299
Kochukhov, O., Makaganiuk, V., Piskunov, N.: Least-squares deconvolution of the stellar intensity and polarization spectra. Astron. Astrophys. 524, A5 (2010). https://doi.org/10.1051/0004-6361/201015429. 1008.5115 [astro-ph.SR]
Kurucz, R.L.: SYNTHE spectrum synthesis programs and line data. Smithsonian Astrophysical Observatory (1993)
Landi Degl’Innocenti, E., Landolfi, M.: Polarization in Spectral Lines, vol. 307 (2004). https://doi.org/10.1007/978-1-4020-2415-3
Landstreet, J.D.: The magnetic field and abundance distribution geometry of the peculiar A Star 53 Camelopardalis. Astrophys. J. 326, 967 (1988). https://doi.org/10.1086/166155
Lavail, A.: CRIRES+: enabling high-resolution near-infrared spectroscopy and spectropolarimetry at the 8-m very large telescope. In: The 20.5th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun (CS20.5), Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, p. 77 (2021). https://doi.org/10.5281/zenodo.4562690
Leroy, J.L.: On the intensity of magnetic field in quiescent prominences. Astron. Astrophys. 60(1), 79–84 (1977)
López Ariste, A., Asensio Ramos, A., González Fernández, C.: Photospheric Hanle diagnostic of weak magnetic dipoles in stars. Astron. Astrophys. 527, A120 (2011). https://doi.org/10.1051/0004-6361/201015388. 1011.6288 [astro-ph.SR]
Manso Sainz, R., Martínez González, M.J.: Hanle effect for stellar dipoles and quadrupoles. Astrophys. J. 760(1), 7 (2012). https://doi.org/10.1088/0004-637X/760/1/7. 1209.6187 [astro-ph.SR]
Manso Sainz, R., Trujillo Bueno, J.: Scattering polarization and Hanle effect in stellar atmospheres with horizontal inhomogeneities. Astrophys. J. 743(1), 12 (2011). https://doi.org/10.1088/0004-637X/743/1/12. 1108.2958 [astro-ph.SR]
Marcolino, W.L.F., Bouret, J.C., Sundqvist, J.O., et al.: Phase-resolved ultraviolet spectroscopy of the magnetic Of?p star HD 191612. Mon. Not. R. Astron. Soc. 431(3), 2253–2260 (2013). https://doi.org/10.1093/mnras/stt323. 1302.4708 [astro-ph.SR]
Martínez González, M.J., Manso Sainz, R., Asensio Ramos, A., et al.: Spectro-polarimetric imaging reveals helical magnetic fields in solar prominence feet. Astrophys. J. 802(1), 3 (2015). https://doi.org/10.1088/0004-637X/802/1/3. 1501.03295 [astro-ph.SR]
Martioli, E., Hébrard, G., Moutou, C., et al.: Spin-orbit alignment and magnetic activity in the young planetary system AU MIC. Astron. Astrophys. 641, L1 (2020). https://doi.org/10.1051/0004-6361/202038695. 2006.13269 [astro-ph.SR]
Moutou, C., Dalal, S., Donati, J.F., et al.: Early science with SPIRou: near-infrared radial velocity and spectropolarimetry of the planet-hosting star HD 189733. Astron. Astrophys. 642, A72 (2020). https://doi.org/10.1051/0004-6361/202038108. 2008.05411 [astro-ph.EP]
Nazé, Y., Sundqvist, J.O., Fullerton, A.W., et al.: The changing UV and X-ray properties of the Of?p star CPD -28°2561. Mon. Not. R. Astron. Soc. 452(3), 2641–2653 (2015). https://doi.org/10.1093/mnras/stv1445. 1506.08572 [astro-ph.SR]
Oksala, M.E., Kochukhov, O., Krtička, J., et al.: Revisiting the rigidly rotating magnetosphere model for \(\sigma\) Ori E – II. Magnetic Doppler imaging, arbitrary field RRM, and light variability. Mon. Not. R. Astron. Soc. 451(2), 2015–2029 (2015). https://doi.org/10.1093/mnras/stv1086. 1505.04839 [astro-ph.SR]
Orozco Suárez, D., Asensio Ramos, A., Trujillo Bueno, J.: The magnetic field configuration of a solar prominence inferred from spectropolarimetric observations in the He i 10 830 Å triplet. Astron. Astrophys. 566, A46 (2014). https://doi.org/10.1051/0004-6361/201322903. 1403.7976 [astro-ph.SR]
Owocki, S.P., ud-Doula, A., Sundqvist, J.O., et al.: An ‘analytic dynamical magnetosphere’ formalism for X-ray and optical emission from slowly rotating magnetic massive stars. Mon. Not. R. Astron. Soc. 462(4), 3830–3844 (2016). https://doi.org/10.1093/mnras/stw1894. 1607.08568 [astro-ph.SR]
Pertenais, M., Neiner, C., Bouillot, A., et al.: Optical design of Arago’s spectropolarimeter. in: Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series p. 105622A (2017). https://doi.org/10.1117/12.2296215
Petit, P., Lignières, F., Aurière, M., et al.: Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic? Astron. Astrophys. 532, L13 (2011). https://doi.org/10.1051/0004-6361/201117573. 1106.5363 [astro-ph.SR]
Petit, P., Folsom, C.P., Donati, J.F., et al.: Multi-instrumental view of magnetic fields and activity of \(\epsilon \) Eridani with SPIRou, NARVAL, and TESS. Astron. Astrophys. 648, A55 (2021). https://doi.org/10.1051/0004-6361/202040027. 2101.02643 [astro-ph.SR]
Piskunov, N., Kochukhov, O.: Doppler imaging of stellar magnetic fields. I Techniques. Astron. Astrophys. 381, 736–756 (2002). https://doi.org/10.1051/0004-6361:20011517
Raouafi, N.E., Sahal-Bréchot, S., Lemaire, P.: Linear polarization of the O VI lambda 1031.92 coronal line. II. Constraints on the magnetic field and the solar wind velocity field vectors in the coronal polar holes. Astron. Astrophys. 396, 1019–1028 (2002). https://doi.org/10.1051/0004-6361:20021418
Ryabchikova, T., Piskunov, N., Kurucz, R.L., et al.: A major upgrade of the VALD database. Phys. Scr. 90(5), 054005 (2015). https://doi.org/10.1088/0031-8949/90/5/054005
Scowen, P.A., Gayley, K., Neiner, C., et al.: The Polstar High Resolution Spectropolarimetry MIDEX Mission. Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series p. 1181908 (2021). https://doi.org/10.1117/12.2594267. 2108.10729[astro-ph.IM]
Scowen, P.A., Gayley Ignace R, K.G., et al.: The Polstar high resolution spectropolarimetry MIDEX mission. Astrophys. Space Sci. 367 (2022). https://doi.org/10.1007/s10509-022-04107-9
Shultz, M.E., Casini, R., Cheung, M.C.M., et al.: Ultraviolet spectropolarimetry with Polstar: using Polstar to test magnetospheric mass-loss quenching. Astrophys. Space Sci. 367 (2022). https://doi.org/10.1007/s10509-022-04113-x
Stenflo, J.: Solar Magnetic Fields: Polarized Radiation Diagnostics, vol. 189. Springer, Berlin (1994). https://doi.org/10.1007/978-94-015-8246-9
Stenflo, J.O., Keller, C.U., Gandorfer, A.: Differential Hanle effect and the spatial variation of turbulent magnetic fields on the Sun. Astron. Astrophys. 329, 319–328 (1998)
Trujillo Bueno, J., Landi Degl’Innocenti, E., Collados, M., et al.: Selective absorption processes as the origin of puzzling spectral line polarization from the Sun. Nature 415(6870), 403–406 (2002). astro-ph/0201409 [astro-ph]
Trujillo Bueno, J., Shchukina, N., Asensio Ramos, A.: A substantial amount of hidden magnetic energy in the quiet Sun. Nature 430(6997), 326–329 (2004). https://doi.org/10.1038/nature02669. astro-ph/0409004 [astro-ph]
ud-Doula, A., Owocki, S.P.: Dynamical simulations of magnetically channeled line-driven stellar winds. I. Isothermal, nonrotating, radially driven flow. Astrophys. J. 576(1), 413–428 (2002). https://doi.org/10.1086/341543. astro-ph/0201195 [astro-ph]
ud-Doula, A., Sundqvist, J.O., Owocki, S.P., et al.: First 3DMHD simulation of a massive-star magnetosphere with application to H\(\alpha\) emission from \(\theta\)1 Ori C. Mon. Not. R. Astron. Soc. 428(3), 2723–2730 (2013). https://doi.org/10.1093/mnras/sts246. 1210.5298 [astro-ph.SR]
ud-Doula, A., Cheung, M.C.M., David-Uraz, A., et al.: Ultraviolet spectropolarimetric diagnostics of hot star magnetospheres. Astrophys. Space Sci. 367 (2022). https://doi.org/10.1007/s10509-022-04097-8
Wade, G.A., Donati, J.F., Landstreet, J.D., et al.: High-precision magnetic field measurements of Ap and Bp stars. Mon. Not. R. Astron. Soc. 313(4), 851–867 (2000a). https://doi.org/10.1046/j.1365-8711.2000.03271.x
Wade, G.A., Donati, J.F., Landstreet, J.D., et al.: Spectropolarimetric measurements of magnetic Ap and Bp stars in all four Stokes parameters. Mon. Not. R. Astron. Soc. 313(4), 823–850 (2000b). https://doi.org/10.1046/j.1365-8711.2000.03273.x
Wade, G.A., Bagnulo, S., Kochukhov, O., et al.: LTE spectrum synthesis in magnetic stellar atmospheres. The interagreement of three independent polarised radiative transfer codes. Astron. Astrophys. 374, 265–279 (2001). https://doi.org/10.1051/0004-6361:20010735
Zhao, J., Gibson, S.E., Fineschi, S., et al.: Simulating the solar corona in the forbidden and permitted lines with forward modeling. I. Saturated and unsaturated Hanle regimes. Astrophys. J. 883(1), 55 (2019). https://doi.org/10.3847/1538-4357/ab328b
Zhao, J., Gibson, S.E., Fineschi, S., et al.: Simulating the solar minimum corona in UV wavelengths with forward modeling II. Doppler dimming and microscopic anisotropy effect. Astrophys. J. 912(2), 141 (2021). https://doi.org/10.3847/1538-4357/abf143
Funding
C.E. gratefully acknowledges support for this work provided by NASA through grant number HST-AR-15794.001-A from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.
R.I. and C.E. gratefully acknowledge that this material is based upon work supported by the National Science Foundation under Grant No. AST-2009412.
M.E.S. acknowledges financial support from the Annie Jump Cannon Fellowship, supported by the University of Delaware and endowed by the Mount Cuba Astronomical Observatory.
G.A.W. acknowledges Discovery Grant support from the Natural Sciences and Engineering Research Council of Canada (NSERC).
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All authors contributed to the preparation of the manuscript. The modelling and analysis in Sect. 2 was primarily done by K.H., C.P.F., and G.A.W. The analysis and modelling in Sect. 3 was primarily completed by C.E., with advisement from V.P. The analysis and modelling in Sect. 4 was primarily done by R.I., R.C., T.P.A., and R.M.S.
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Folsom, C.P., Ignace, R., Erba, C. et al. Ultraviolet spectropolarimetry: investigating stellar magnetic field diagnostics. Astrophys Space Sci 367, 125 (2022). https://doi.org/10.1007/s10509-022-04140-8
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DOI: https://doi.org/10.1007/s10509-022-04140-8