Related papers: Accretion, jets and winds: High-energy emission fr…

T Tauri stars are young, low mass, pre-main sequence stars surrounded by an accretion disk. These objects present strong magnetic activity and powerful magnetic reconnection events. Strong shocks are likely produced in the stellar…

We use the data of the Chandra Orion Ultradeep Project (COUP) to study the nearly 600 X-ray sources that can be reliably identified with optically well characterized T Tauri stars (TTS) in the Orion Nebula Cluster. We detect X-ray emission…

X-ray emission from stars has origins as diverse as the stars themselves: accretion shocks, shocks generated in wind-wind collisions, or release of magnetic energy. Although the scenarios responsible for X-ray emission are thought to be…

Intermediate dispersion spectroscopic observations of 37 Herbig Ae/Be stars reveal that the equivalent widths of their [OI] 6300A and Halpha emission lines, are related to their near-infrared colours in the same fashion as the T-Tauri…

T Tauri Stars (TTSs) are magnetically active stars that accrete matter from the inner border of the surrounding accretion disc; plasma gets trapped into the large scale magnetic structures and falls onto the star, heating the surface…

Episodic accretion plays an important role in the evolution of young stars. Although it has been under investigation for a long time, the origin of such episodic accretion events is not yet understood. We investigate the dust and gas…

Classical T Tauri stars (CTTS) differ in their X-ray signatures from older pre-main sequence stars, e.g. weak-lined TTS (WTTS). CTTS show a soft excess and deviations from the low-density coronal limit in the He-like triplets. We test…

Using three XMM-Newton observations we study the X-ray emission of RU Lup, a accreting and wind-driving CTTS. In comparison with other bright CTTS we study possible signatures of accretion and winds in their X-ray emission. Results: We find…

Stars form by accreting material from their surrounding disks. There is a consensus that matter flowing through the disk is channelled onto the stellar surface by the stellar magnetic field. This is thought to be strong enough to truncate…

We discuss the properties of an accretion disk around a star with parameters typical of classical T Tauri stars (CTTS), and with the average accretion rate for these disks. The disk is assumed steady and geometrically thin. The turbulent…

Photoevaporation caused by X-rays and ultraviolet radiation from the central star has attracted attention as a key process driving the dispersal of protoplanetary discs. Although numerous models have been used to investigate the…

In the initial formation stages young stars must acquire a significant fraction of their mass by accretion from a circumstellar disk that forms in the center of a collapsing protostellar cloud. Throughout this period mass accretion rates…

T Coronae Borealis (T CrB) is a nearby recurrent nova expected to erupt in the near future, offering a unique opportunity to study particle acceleration and high-energy emission from novae in real time. We investigate the production of…

Aims: We attempt to determine the masses of single or multiple young T Tauri and HAeBe stars from the rotation of their Keplerian disks. Methods:We used the IRAM PdBI interferometer to perform arcsecond resolution images of the CN N=2-1…

We report on accretion- and outflow-related X-rays from T Tauri stars, based on results from the "XMM-Newton Extended Survey of the Taurus Molecular Cloud." X-rays potentially form in shocks of accretion streams near the stellar surface,…

Young stars accrete mass from a circumstellar disk, but at the same time disk and star eject outflows and jets. These outflows have an onion-like structure where the innermost and fastest layers are surrounded by increasingly lower velocity…

We perform local excitation calculations to obtain line opacities and emissivity ratios and compare them with observed properties of H, He I, O I, Ca II, and Na I lines to determine the density, temperature, and photon ionization rate. We…

Young, low-mass stars are luminous X-ray sources whose powerful X-ray flares may exert a profound influence over the process of planet formation. The origin of such emission is uncertain. Although many or perhaps most recently formed,…

We present optical spectra of 45 intermediate mass Herbig Ae/Be stars. Together with the multi-epoch spectroscopic and photometric data compiled for a large sample of these stars and ages estimated for individual stars by using pre-main…

We developed a grid of stellar rotation models for low-mass and solar-type Classical T Tauri stars (CTTS) ($0.3M_{\odot}<M_{\ast}<1.2M_{\odot}$). These models incorporate the star-disk interaction and magnetospheric ejections to investigate…