Related papers: The Angular Momentum Content and Evolution of Clas…

We present a large-scale study of stellar rotation for T Tauri stars in the Orion Star-Forming Complex. We use the projected rotational velocity ($v\sin(i)$) estimations reported by the APOGEE-2 collaboration as well as individual masses…

We have studied the kinematic properties of young pre-main-sequence stars. We have selected these stars based on data from the Gaia DR2 catalogue by invoking a number of photometric infrared surveys. Using 4564 stars with parallax errors…

Strong stellar magnetic fields are believed to truncate the inner accretion disks around young stars, redirecting the accreting material to the high latitude regions of the stellar surface. In the past few years, observations of strong…

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…

We present the first spectrum of a highly veiled, strongly accreting protostar which shows photospheric absorption features and demonstrates the stellar nature of its central core. We find the spectrum of the luminous (L_bol = 10 L_sun)…

The ASCA satellite has recently detected variable hard X-ray emission from two Class I protostars in the rho Oph cloud, YLW15 (IRS43) and WL6, with a characteristic time scale ~20h. In YLW15, the X-ray emission is in the form of…

[abridged] Understanding how the infalling gas redistribute most of its initial angular momentum inherited from prestellar cores before reaching the stellar embryo is a key question. Disk formation has been naturally considered as a…

The spectral and spatial characteristics of two special categories of O stars found in the VFTS dataset are presented. One of them comprises very rapid rotators, including several more extreme than any previously known. These objects are…

(Abridged) Projected rotational velocities (vsini) have been measured for a sample of 145 stars with masses between 0.4 and >10 Msun (median mass 2.1 Msun) located in the Orion star-forming complex. These measurements have been supplemented…

In recent years, there has been a number of detections of gradients in the radial velocity profile across jets from young stars. The significance of these results is considerable. They may be interpreted as a signature of jet rotation about…

A major uncertainty in the theory of stellar evolution is the angular momentum distribution inside stars and its change during stellar life. We compose a sample of 67 stars in the core-hydrogen burning phase with a $\log\,g$ value from…

The evolution of rotating stars with zero-age main sequence (ZAMS) masses in the range 8 to 25 M_sun is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational…

When they first appear in the HR diagram, young stars rotate at a mere 10\% of their break-up velocity. They must have lost most of the angular momentum initially contained in the parental cloud, the so-called angular momentum problem. We…

The core rotation rates of massive stars have a substantial impact on the nature of core-collapse supernovae and their compact remnants. We demonstrate that internal gravity waves (IGW), excited via envelope convection during a red…

(abridged) Our project endeavors to obtain a robust view of multiplicity among embedded Class I and Flat Spectrum protostars in a wide array of nearby molecular clouds to disentangle ``universal'' from cloud-dependent processes. We have…

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…

In young circumstellar disks, accretion--the inspiral of disk material onto the central star--is important for both the buildup of stellar masses and the outcome of planet formation. Although the existence of accretion is well documented,…

We develop equations and obtain solutions for the structure and evolution of a protodisc region that is initially formed with no radial motion and super-Keplerian rotation speed when wind material from a hot rotating star is channelled…

We analyzed the behavior of the rotational velocity in the parent stars of extrasolar planets. Projected rotational velocity v sin i and angular momentum were combined with stellar and planetary parameters, for a unique sample of 147 stars,…

Classical T Tauri stars (CTTSs) are young low-mass stellar objects accreting mass from their circumstellar disks. They are characterized by high levels of coronal activity as revealed by X-ray observations. This activity may affect the disk…