Related papers: Polar Fields for AB Dor
A study of the unbalanced magnetic polarity distribution of 70 coronal holes was performed. Data from the Helioseismic and Magnetic Imager (HMI) were used to examine the photospheric line-of-sight magnetic field ($B_{\mathrm{LOS}}$) beneath…
In this study we present simultaneous low-resolution longitudinal magnetic field measurements and high-resolution spectroscopic observations of the cool single giant FK Com. The variation of the magnetic field over the rotational period of…
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…
Simulations of magnetohydrodynamics convection in slowly rotating stars predict anti-solar differential rotation (DR) in which the equator rotates slower than poles. This anti-solar DR in the usual $\alpha \Omega$ dynamo model does not…
Recent XMM-Newton observations of the B2 type star rho Oph A indicated a periodicity of 1.205d, which was ascribed to rotational modulation. Since variability of X-ray emission in massive stars is frequently the signature of a magnetic…
Rapid rotation enhances the dynamo operating in stars, and thus also introducessignificantly stronger magnetic activity than is seen in slower rotators. Many young cool stars still have the rapid, primordial rotation rates induced by the…
The goal of this work is to study the magnetic fields of six young solar-analogue stars both individually, and collectively, to search for possible magnetic field trends with age. If such trends are found, they can be used to understand…
The solar photospheric magnetic field is highly structured owing to its interaction with the convective flows. Its local structure has a strong influence on the profiles of spectral lines not only by virtue of the Zeeman effect, but also…
Synoptic magnetograms and relevant proxy data were analyzed to study the evolution of the Sun's polar magnetic fields. Time-latitude analysis of large-scale magnetic fields demonstrates cyclic changes in their zonal structure and the…
Recent spectropolarimetric observations of active region filaments have revealed polarization profiles with signatures typical of the strong field Zeeman regime. The conspicuous absence in those observations of scattering polarization and…
We theoretically study the structure of a stationary soliton in the polar phase of spin-1 Bose--Einstein condensate in the presence of quadratic Zeeman effect at zero temperature. The phase diagram of such solitons is mapped out by finding…
Historically, the magnetic field geometries of the chemically peculiar Ap stars were modelled in the context of a simple dipole field. However, with the acquisition of increasingly sophisticated diagnostic data, it has become clear that the…
Using spectropolarimetric data of an Active Region (AR) filament we have carried out inversions in order to infer vector magnetic fields in the photosphere (Si I line) and in the chromosphere (He I line). Our filament lies above the…
The solar magnetic structure changes over the solar cycle. It has a dipole structure during solar minimum, where the open flux extends mainly from the polar regions into the interplanetary space. During maximum, a complex structure is…
Using the polar vector magnetic field data observed by Hinode from 2012 to 2021, we study the long-term variations of the magnetic flux, the flux proportion of different polarities, and the magnetic inclination with respect to the local…
Using magnetic field maps acquired by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory we measured rotation rates of 864 active and 322 ephemeral regions observed between 2010 and 2016. We found smaller magnetic…
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…
On the AGB, low to intermediate mass stars blow away their outer envelopes, forming planetary nebulae. Interaction between the planetary nebula and its central progenitor is poorly understood and even more complex when the central object is…
Context. Recent high angular resolution polarimetric continuum observations of circumstellar disks provide new insights into their magnetic field. However, direct constraints are limited to the plane of sky component of the magnetic field.…
About 20% of the white dwarfs possess a magnetic field that may be detected by the splitting and/or polarization of their spectral lines. As they cool, the effective temperatures of the white dwarfs becomes so low that no spectral lines can…