Related papers: Large-scale magnetic topologies of M dwarfs
We present a spectroscopic analysis of nearly 8000 late-type dwarfs in the Sloan Digital Sky Survey. Using the Halpha emission line as an activity indicator, we investigate the fraction of active stars as a function of spectral type and…
Magnetic massive stars -- which are being discovered with increasing frequency -- represent a new category of wind-shaping mechanism for O and B stars. Magnetic channeling of these stars' radiation-driven winds, the Magnetically Confined…
The dynamo processes in cool active stars generate complex magnetic fields responsible for prominent surface stellar activity and variability at different time scales. For a small number of cool stars magnetic field topologies were…
Observations of magnetism in very low mass stars recently made important progress, revealing characteristics that are now to be understood in the framework of dynamo theory. In parallel, there is growing evidence that dynamo processes in…
The release of spin-down energy by a magnetar is a promising scenario to power several classes of extreme explosive transients. However, it lacks a firm basis because magnetar formation still represents a theoretical challenge. Using the…
We present first results from three-dimensional radiation magnetohydrodynamic simulations of M-type dwarf stars with CO5BOLD. The local models include the top of the convection zone, the photosphere, and the chromosphere. The results are…
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…
The surface rotation rates of young solar-type stars decrease rapidly with age from the end of the pre-main sequence though the early main sequence. This suggests that there is also an important change in the dynamos operating in these…
The aim of this work is to investigate rotation profile of solar-like stars with magnetic fields. A diffusion coefficient of magnetic angular momentum transport is deduced. Rotating stellar models with different mass are computed under the…
The dynamo action achieved in the convective cores of main-sequence massive stars is explored here through 3D global simulations of convective core dynamos operating within a young $\Msun{10}$ B-type star, using the anelastic spherical…
Accounting for stellar activity is a crucial component of the search for ever-smaller planets orbiting stars of all spectral types. We use Doppler imaging methods to demonstrate that starspot induced radial velocity variability can be…
The aim of this study is to explore the magnetic and flow properties of fully convective M dwarfs as a function of rotation period Prot and magnetic Reynolds ReM and Prandlt numbers PrM. We performed three-dimensional simulations of fully…
Surface rotation rates of young solar-type stars display drastic changes at the end of the pre-main sequence through the early main sequence. This may trigger corresponding changes in the magnetic dynamos operating in these stars, which…
Massive star winds are important contributors to the energy, momentum and chemical enrichment of the interstellar medium. Strong, organized and predominantly dipolar magnetic fields have been firmly detected in a small subset of massive…
A 2D dynamic model is utilized to investigate star formation in rotating filamentary molecular clouds (FMCs) amidst magnetic fields. The study reveals that the emergence of field stars is possible under both weak and strong magnetic fields…
We have measured v sin i with high precision for a sample of dM3 stars (86 targets). We detected rotation in 82 stars (73 dM3 stars, and 9 dM3e stars). We compare our measurements of v sin i for all the stars in our dM0, dM2, dM3 and dM4…
To investigate statistically whether magnetic fields in massive stars are ubiquitous or appear in stars with specific spectral classification, certain ages, or in a special environment, we acquired 41 new spectropolarimetric observations…
We study effects of the cross-helicity in the full-sphere large-scale mean-field dynamo models of the 0.3M star rotating with the period of 10 days. In exploring several dynamo scenarios which are stemming from the cross-helicity generation…
The main observational results from radio continuum and polarization observations about the magnetic field strength and large-scale pattern for face-on and edge-on spiral galaxies are summarized and compared within our sample of galaxies of…
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…