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Magnetic fields are ubiquitous in active cool stars but they are in general complex and weak. Current Zeeman Doppler imaging (ZDI) studies of cool star magnetic fields chiefly employ circular polarization observations because linear…

Solar and Stellar Astrophysics · Physics 2015-06-03 Lisa Rosén , Oleg Kochukhov , Gregg A. Wade

Low-mass stars are known to have magnetic fields that are believed to be of dynamo origin. Two complementary techniques are principally used to characterise them. Zeeman-Doppler imaging (ZDI) can determine the geometry of the large-scale…

Zeeman-Doppler imaging (ZDI) is used to study the surface magnetic field topology of stars, based on high-resolution spectropolarimetric time series observations. Multiple ZDI inversions have been conducted for the early B-type star tau…

Solar and Stellar Astrophysics · Physics 2025-07-02 Jennifer Rosina Andersson , Oleg Kochukhov , Zheng Zhao , Jens Sjölund

M dwarfs host strong magnetic fields that can be measured using several complementary techniques. However, the impact of key methodological choices on Zeeman broadening diagnostics has not been systematically quantified. We assess the…

Solar and Stellar Astrophysics · Physics 2026-05-19 I. Amateis , O. Kochukhov , A. Hahlin

Zeeman-Doppler Imaging (ZDI) is a powerful inversion method to reconstruct stellar magnetic surface fields. The reconstruction process is usually solved by translating the inverse problem into a regularized least-square or optimization…

Solar and Stellar Astrophysics · Physics 2009-11-13 T. A. Carroll , M. Kopf , K. G. Strassmeier , I. Ilyin

The major challenges for a fully polarized radiative transfer driven approach to Zeeman-Doppler imaging are still the enormous computational requirements. In every cycle of the iterative interplay between the forward process (spectral…

Astrophysics · Physics 2008-07-25 T. A. Carroll , M. Kopf , K. G. Strassmeier

The large-scale magnetic fields of stars can be obtained with the Zeeman-Doppler-Imaging (ZDI) technique, but their interpretation is still challenging as the contribution of the small-scale field or the reliability of the reconstructed…

Solar and Stellar Astrophysics · Physics 2019-01-09 L. T. Lehmann , G. A. J. Hussain , M. M. Jardine , D. H. Mackay , A. A. Vidotto

Aims: The goal of this study is to perform numerical tests of Zeeman Doppler Imaging (ZDI) to asses whether correct reconstruction of magnetic fields is at all possible without taking temperature into account for stars in which magnetic and…

Solar and Stellar Astrophysics · Physics 2012-11-13 Lisa Rosén , Oleg Kochukhov

Information about stellar magnetic field topologies is obtained primarily from high-resolution circular polarisation (Stokes $V$) observations. Due to their generally complex morphologies, the stellar Stokes $V$ profiles are usually…

Solar and Stellar Astrophysics · Physics 2015-07-29 O. Kochukhov

We have developed a new method to derive the magnetic field distribution on the surfaces of rotating magnetic white dwarfs from phase-resolved flux and circular polarization spectra. An optimization code based on an evolutionary strategy is…

Astrophysics · Physics 2007-05-23 F. Euchner , K. Beuermann , K. Reinsch , S. Jordan , F. V. Hessman , B. T. Gaensicke

The observation of the polarization emerging from a rotating star at different phases opens up the possibility to map the magnetic field in the stellar surface thanks to the well-known Zeeman Doppler Imaging. When the magnetic field is…

Solar and Stellar Astrophysics · Physics 2015-06-05 M. J. Martínez González , A. Asensio Ramos

Zeeman-Doppler imaging (ZDI) is used to reconstruct the surface magnetic field of late-type stars from high resolution spectropolarimetric observations. The results are usually described in terms of characteristics of the field topology,…

Solar and Stellar Astrophysics · Physics 2024-01-23 Thomas Hackman , Oleg Kochukhov , Mariangela Viviani , Jörn Warnecke , Maarit J. Korpi-Lagg , Jyri J. Lehtinen

Zeeman Doppler Imaging is a powerful tool for characterizing the strength and topology of stellar magnetic fields. In this research note, we present a new way to visualize the typical results from ZDI for an ensemble of stars, addressing…

Solar and Stellar Astrophysics · Physics 2020-06-11 J. Sebastian Pineda , James R. A. Davenport

Global magnetic fields of active solar-like stars are nowadays routinely detected with spectropolarimetric measurements and are mapped with Zeeman-Doppler imaging (ZDI). However, due to the cancellation of opposite field polarities,…

Solar and Stellar Astrophysics · Physics 2020-03-25 O. Kochukhov , T. Hackman , J. J. Lehtinen , A. Wehrhahn

Context. The interplay between surface magnetic topology and chromospheric heating in active M dwarfs remains poorly constrained, limiting our understanding of their magnetic cycles and high-energy environments. Aims. We aim to test whether…

Solar and Stellar Astrophysics · Physics 2025-10-28 Shuai Liu , Jianrong Shi , Huigang Wei , Wenxian Li , Jifeng Liu , Shangbin Yang , Henggeng Han

In this paper we present an analysis of the first high-resolution full Stokes vector spectropolarimetric observations of the active M dwarf AD Leo. Based on observations collected in 2016 with the ESPaDOnS instrument at CFHT, we derived the…

Solar and Stellar Astrophysics · Physics 2018-08-01 Alexis Lavail , Oleg Kochukhov , Gregg Wade

The early B-type star tau Sco exhibits an unusually complex, relatively weak surface magnetic field. Its topology was previously studied with the Zeeman Doppler imaging (ZDI) modelling of high-resolution circular polarisation (Stokes V)…

Solar and Stellar Astrophysics · Physics 2016-02-03 O. Kochukhov , G. A. Wade

In this paper we show how tomographic imaging (Zeeman Doppler Imaging, ZDI) can be used to characterize stellar activity and magnetic field topologies, ultimately allowing to filter out the radial velocity (RV) activity jitter of M-dwarf…

Solar and Stellar Astrophysics · Physics 2016-06-15 É. M. Hébrard , J. -F. Donati , X. Delfosse , J. Morin , C. Moutou , I. Boisse

The topic of magnetic field diagnostics with the Zeeman effect is currently vividly discussed. There are some testable inversion codes available to the spectropolarimetry community and their application allowed for a better understanding of…

Solar and Stellar Astrophysics · Physics 2016-11-29 M. Derouich

The evolution of the magnetism, winds and rotation of low-mass stars are all linked. One of the most common ways to probe the magnetic properties of low-mass stars is with the Zeeman-Doppler imaging (ZDI) technique. The magnetic properties…

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