Related papers: Analytic and numerical models of the 3D multipolar…
Classical T Tauri stars (CTTSs) are young stellar objects that accrete materials from their accretion disc influenced by their strong magnetic field. The magnetic pressure truncates the disc at a few stellar radii and forces the material to…
The magnetic field topology in the surrounding of neutron stars is one of the key questions in pulsar magnetospheric physics. A very extensive literature exists about the assumption of a dipolar magnetic field but very little progress has…
We have produced brightness and magnetic field maps of the surfaces of CV Cha and CR Cha: two actively accreting G and K-type T Tauri stars in the Chamaeleon I star-forming cloud with ages of 3-5 Myr. Our magnetic field maps show evidence…
From a long time series of high resolution (R=115,000) HARPS spectra and simultaneous broad-band photometry, we report new evidence for magnetospheric accretion as well as ejection processes in the nearly edge-on classical T Tauri star AA…
Models of magnetically driven accretion and outflows reproduce many observational properties of T Tauri stars, but the picture is much less clear for the Herbig Ae/Be stars, due to the poor knowledge of their magnetic field strength and…
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…
From observations collected with the ESPaDOnS & NARVAL spectropolarimeters at CFHT and TBL, we report the detection of Zeeman signatures on the prototypical classical TTauri star AATau, both in photospheric lines and accretion-powered…
Accretion onto Classical T Tauri stars is thought to take place through the action of magnetospheric processes, with gas in the inner disk being channeled onto the star's surface by the stellar magnetic field lines. Young stars are known to…
We probe the geometry of magnetospheric accretion in classical T Tauri stars by modeling red absorption at He I 10830 via scattering of the stellar and veiling continua. Under the assumptions that the accretion flow is an azimuthally…
CONTEXT. Because of the presence of rotation and accretion disks, classical T Tauri stars have symmetry planes that are normally inclined relative to the plane of the sky. The inclination angles affect the observed spectral properties of…
Classical T Tauri stars (CTTS) accrete material from their discs through their magnetospheres. The geometry of the accretion flow strongly depends on the magnetic obliquity, i.e., the angle between the rotational and magnetic axes. We aim…
We report the results of a synoptic study of the photometric and spectroscopic variability of the classical T Tauri star AA Tau on timescales ranging from a few hours to several weeks. Emission lines show both infall and outflow signatures…
T Tauri stars, in more advanced stages of evolution, during the final accretion phase of stellar formation, exhibit intense stellar winds and surface magnetic fields with intensities around a kilogauss. With the growing interest in the…
An accurate estimation of the continuum excess emission from accretion spots and inner circumstellar disk regions is crucial for a proper derivation of fundamental stellar parameters in accreting systems. However, the presence of starspots…
Context: Observations suggest that magnetic fields of disk-bearing stars may have non-dipolar configurations. However, the influence of these configurations on magnetospheric accretion remains poorly understood. Aims: We aim to simulate…
A general model of magnetically controlled accretion onto T Tauri stars is presented. In this model the magnetic field is oriented arbitrarily in relation to the star's rotation axis. The resultant interplay between the magnetic field and…
Disk-fed accretion onto neutron stars can power a wide range of astrophysical sources ranging from X-ray binaries, to accretion powered millisecond pulsars, ultra-luminous X-ray sources, and gamma-ray bursts. A crucial parameter controlling…
A recipe is presented to construct an analytic, self-consistent model of a non-barotropic neutron star with a poloidal-toroidal field of arbitrary multipole order, whose toroidal component is confined in a torus around the neutral curve…
We compute the properties of a geometrically thin, steady accretion disk surrounding a central rotating, magnetized star. The magnetosphere is assumed to entrain the disk over a wide range of radii. The model is simplified in that we adopt…
We compare accretion shock models with optical and ultraviolet spectra of pre-main sequence stars to (1) make the first determinations of accretion rates in intermediate mass T Tauri stars from continuum emission, and (2) derive improved…