Related papers: Hot-star wind models with magnetically split line …
The theory of radiatively driven winds successfully explains the key points of the stellar winds of hot massive stars. However, there is an apparent break-down of this paradigm at L/Lsun<5.2: the stellar wind momentum is smaller than…
In this chapter, we give a brief introduction into the use of the Zeeman effect in astronomy and the general detection of magnetic fields in stars, concentrating on the use of FORS2 for longitudinal magnetic field measurements.
Direct measurements of magnetic fields in low-mass stars of spectral class M have become available during the last years. This contribution summarizes the data available on direct magnetic measurements in M dwarfs from Zeeman analysis in…
Strong surface magnetic fields are ubiquitously found in M-dwarfs with mean intensities on the order of few thousand Gauss-three orders of magnitude higher than the mean surface magnetic field of the Sun. These fields and their interaction…
Stellar winds of cool, main-sequence stars are very tenuous and difficult to observe. Despite carrying away only a small amount of the stellar mass, they are important for regulating the rotation of the star and, consequently, its activity…
Radiation-driven winds heavily influence the evolution and fate of massive stars. Feedback processes from these winds impact the properties of the interstellar medium of their host galaxies. The dependence of mass loss on stellar properties…
The large-scale field of the Sun is well represented by its lowest energy (or potential) state. Recent observations, by comparison, reveal that many solar-type stars show large-scale surface magnetic fields that are highly non-potential -…
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…
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…
A Zeeman field affects the metallic heavy fermion ground state in two ways: (i) it splits the spin-degerenate conduction sea, leaving spin up and spin down Fermi surfaces with different band curvature; (ii) it competes with the Kondo effect…
By deriving the quantum hydrodynamic equations for an isotropic single-band ferromagnet in an arbitrary magnetic field, we find that a massive mode recently predicted splits under the action of the field. The splitting is a peculiarity of…
We present estimates of magnetic field strengths in the interstellar media of starburst galaxies derived from measurements of Zeeman splitting associated with OH megamasers. The results for eight galaxies with Zeeman detections suggest that…
Context. Observations of Zeeman split spectral lines represent an important approach to derive the structure and strength of magnetic fields in molecular clouds. In contrast to the uncertainty of the spectral line observation itself, the…
About ten percent of all OB stars show strong, large-scale surface magnetic fields. The interaction of the magnetic field and the wind is believed to be the cause for the X-ray emission shown by these objects. We therefore run numerical…
Massive stars are crucial building blocks of galaxies and the universe, as production sites of heavy elements and as stirring agents and energy providers through stellar winds and supernovae. The field of magnetic massive stars has seen…
A multi-line Bayesian analysis of the Zeeman broadening in the solar atmosphere is presented. A hierarchical probabilistic model, based on the simple but realistic Milne-Eddington approximation to the solution of the radiative transfer…
We calculate multicomponent line-driven wind models of stars at extremely low metallicity suitable for massive first generation stars. For most of the models we find that the multicomponent wind nature is not important for either wind…
The characterization of magnetic fields within molecular clouds is fundamental to understanding star formation processes. Accurately gauging the three-dimensional structure of these fields presents a challenge, as observational techniques…
We report on the effect of a weak magnetic field applied on an iodine cell used to frequency stabilize a laser. A 1.5$~\mu$m laser is frequency tripled in order to excite the molecular transitions at 0.51$~\mu$m and frequency locked on a…
Strong, stable, and organised magnetic fields are present at the surfaces of a small fraction of OBA stars. These "fossil fields" exhibit uniform characteristics in stars over a tremendous range of stellar mass, age, temperature, and…