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Related papers: Zeeman-Doppler Imaging : Old Problems and New Meth…

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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

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

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

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

We present a technique that combines Zeeman Doppler imaging (ZDI) principles with a potential field mapping prescription in order to gain more information about the surface field topology of rapid rotators. This technique is an improvement…

Astrophysics · Physics 2009-10-31 G. A. J. Hussain , M. Jardine , A. Collier Cameron

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

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

The modern Doppler Imaging (DI) technique allows the reconstruction of different stellar surface structures based on accurate calculation of spectra of specific intensity. New applications like the mapping of the magnetic field vector put…

Astrophysics · Physics 2007-05-23 N. Piskunov

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

Magnetic activity and rotation are known to be intimately linked for low-mass stars. Understanding rotation evolution over the stellar lifetime is therefore an important goal within stellar astrophysics. In recent years, there has been…

Late-type stars in general possess complicated magnetic surface fields which makes their detection and in particular their modeling and reconstruction challenging. In this work we present a new Zeeman-Doppler imaging code which is…

Astrophysics · Physics 2008-01-03 T. A. Carroll , M. Kopf , I. Ilyin , K. G. Strassmeier

Throughout the last decades, Zeeman-Doppler Imaging (ZDI) has been intensively used to reconstruct large-scale magnetic topologies of active stars from time series of circularly polarized (Stokes $V$) profiles. ZDI being based on the…

Solar and Stellar Astrophysics · Physics 2022-09-28 Benjamin Finociety , Jean-François Donati

Context. A lot of effort has been put into the detection and determination of stellar magnetic fields using the spectral signal obtained from the combination of hundreds or thousands of individual lines, an approach known as multi-line…

Solar and Stellar Astrophysics · Physics 2016-12-07 J. C. Ramírez Vélez , M. J. Stift , S. G. Navarro , J. P. Córdova , L. Sabin , A. Ruelas-Mayorga

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…

Analyses of global magnetic fields in M dwarfs rely on many approximations regarding the derivation of average line profiles from spectropolarimetric data, interpreting them with analytical functions and modelling them using Zeeman Doppler…

Solar and Stellar Astrophysics · Physics 2026-01-28 Oleg Kochukhov

Magnetic particle imaging (MPI) is a medical imaging modality of recent origin, and it exploits the nonlinear magnetization phenomenon to recover the spatially dependent concentration of the nanoparticles. Currently, image reconstruction in…

Numerical Analysis · Mathematics 2019-04-23 Tobias Kluth , Bangti Jin

Insights on stellar surface large-scale magnetic field topologies are usually drawn by applying Zeeman-Doppler-Imaging (ZDI) to the observed spectropolarimetric time series. However, ZDI requires experience for reliable results to be…

Solar and Stellar Astrophysics · Physics 2022-06-02 L. T. Lehmann , J. -F. Donati

The magnetic activity of the Sun changes with the solar cycle. Similar cycles are found in other stars as well, but their details are not known to a similar degree. Characterising stellar magnetic cycles is important for the understanding…

Solar and Stellar Astrophysics · Physics 2022-05-11 T. Willamo , J. J. Lehtinen , T. Hackman , M. J. Käpylä , O. Kochukhov , S. V. Jeffers , H. Korhonen , S. C. Marsden

Magnetic fields of cool stars can be directly investigated through the study of the Zeeman effect on photospheric spectral lines using several approaches. With spectroscopic measurement in unpolarised light, the total magnetic flux averaged…

Context. Magneto-asteroseismology is a novel technique allowing for more precise determinations of internal properties of magnetic pulsating stars, but requires an accurate characterisation of the surface magnetic field, not previously…

Solar and Stellar Astrophysics · Physics 2026-05-06 C. Gutteridge , C. Neiner , C. Catala , C. P. Folsom
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