Related papers: Do accretion-powered stellar winds help spin down …
Much is known about the processes driving accretion from protoplanetary disks onto low-mass pre-main-sequence stars (T Tauri stars). Nevertheless, it is unclear how accretion stops. To determine the accretion properties and their relation…
We present results of axisymmetic magnetohydrodynamic simulations of the interaction of a rapidly-rotating, magnetized star with an accretion disk. The disk is considered to have a finite viscosity and magnetic diffusivity. The main…
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…
Observational data on rotation of Ap stars suggest that the bulk of their rotation rates form a separate Maxwellian distribution with an average value 3-4 times lower than the normal star distribution. No evidences for a significant angular…
The inner region of the accretion disk around a magnetized star (T Tauri star, white dwarf or neutron star) is subjected to magnetic torques that induce warping and precession of the disk. These torques arise from the interaction between…
We consider the spin angular momentum evolution of the accreting components of Algol-type binary stars. In wider Algols the accretion is through a disc so that the accreted material can transfer enough angular momentum to the gainer that…
We compute the evolution and rotational periods of young stars, using the MESA code, starting from a stellar seed, and take protostellar accretion, stellar winds, and the magnetic star-disk interaction into account. Furthermore, we add a…
The angular momentum (AM) evolution of stellar interiors, along with the resulting rotation rates of stellar remnants, remains poorly understood. Asteroseismic measurements of red giant stars reveal that their cores rotate much faster than…
We formulate a general, steady-state model for the torque on a magnetized star from a surrounding accretion disc. For the first time, we include the opening of dipolar magnetic field lines due to the differential rotation between the star…
We investigate a sample of 6 Herbig Ae/Be stars belonging to the Orion OB1 association, as well as 73 low mass objects, members of the $\sigma$ Orionis cluster, in order to explore the angular momentum evolution at early stages of…
Motivated by measurements of the rotation speed of accretor stars in post-mass-transfer (post-MT) systems, we investigate how magnetic braking affects the spin-down of individual stars during binary evolution with the MESAbinary module.…
We present numerical solutions of the collapse of prestellar cores that lead to the formation and evolution of circumstellar disks. The disk evolution is then followed for up to three million years. A variety of models of different initial…
The early pre-main sequence phase during which they are still likely surrounded by an accretion disk represents a puzzling stage of the rotational evolution of solar-mass stars. While they are still accreting and contracting they do not…
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…
Recent observations show a strong correlation between stellar mass and accretion rate in young stellar and sub-stellar objects, with the scaling $\dot{M}_{acc} \propto M_*^2$ holding over more than four orders of magnitude in accretion…
The accretion process in young stellar objects (YSOs) is fundamental to the formation of stellar systems. This process governs the star's mass assembly, the transfer of angular momentum, and the shaping of the protoplanetary disc, thereby…
We review observational evidence and open issues related to the process of magnetospheric accretion in T Tauri stars. Emphasis is put on recent numerical simulations and observational results which suggest that the interaction between the…
Photometric observations of accreting, low-mass, pre-main-sequence stars (i.e., Classical T Tauri stars; CTTS) have revealed different categories of variability. Several of these classifications have been linked to changes in $\dot{M}$. To…
Nearby associations are excellent objects for the study of the initial spin up phase during the PMS evolution. An empirical approach is adopted here to infer their rotations properties and relations to X-ray emission. Three nearby…
Modeling the rotation history of solar-type stars is still an unsolved problem in modern astrophysics. One of the main challenges is to explain the dispersion in the distribution of stellar rotation rate for young stars. Previous works have…