Related papers: Pre main sequence: Accretion & Outflows

The driving mechanism of protostellar outflows and jets and their effects on the star formation process obtained from recent theoretical and numerical studies are described. Low-velocity outflows are driven by an outer region of the…

A solid theoretical understanding of how inflowing, accreting plasma around black holes and other compact objects gives rise to outflowing winds and jets is still lacking, despite decades of observations. The fact that similar processes and…

The mass growth of protostars is a central element to the determination of fundamental stellar population properties such as the initial mass function. Constraining the accretion history of individual protostars is therefore an important…

Studying outflows from young massive star-forming clusters allows one to deduce physical processes that lead to the formation of the most massive stars. I will review the current state of high-spatial-resolution interferometric (sub-)mm…

(abridged) Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Low-mass stars on the cooler part of the main sequence and their pre-main sequence predecessors define the dominant stellar population in the galaxy…

We review some aspects of the bipolar molecular outflow phenomenon. In particular, we compare the morphological properties, energetics and velocity structures of outflows from high and low-mass protostars and investigate to what extent a…

Mass accretion onto (proto-)stars at high accretion rates > 10^-4 M_sun/yr is expected in massive star formation. We study the evolution of massive protostars at such high rates by numerically solving the stellar structure equations. In…

Jets and outflows are ubiquitous in the process of formation of stars since outflow is intimately associated with accretion. Free-free (thermal) radio continuum emission is associated with these jets. This emission is relatively weak and…

The last decade has witnessed significant advances in our observational understanding of the earliest stages of low-mass star formation. The advent of sensitive receivers on large radio telescopes such as the JCMT and IRAM 30m MRT has led…

The earliest phases of star formation are characterised by intense mass accretion from the circumstellar disk to the central star. One group of young stellar objects, the FU Orionis-type stars exhibit accretion rate peaks accompanied by…

Young stellar objects are thought to commonly undergo sudden accretion events that result in a rise in bolometric luminosity. These outbursts likely coincide with the onset of planet formation, and could impact the formation of planets. The…

We have searched for massive molecular outflows in a sample of high-mass star forming regions, and we have characterised both the outflow properties and those of their associated molecular clumps. With a sample composed largely of more…

We have surveyed 84 Class 0, Class I, and flat-spectrum protostars in mid-infrared [Si II], [Fe II] and [S I] line emission, and 11 of these in far-infrared [O I] emission. We use the results to derive their mass outflow rates. Thereby we…

Main-sequence stars follow a well-defined rotation-activity relation. There are two primary regimes: saturated, where the fractional X-ray luminosity $\log(L_{\rm X}/L_*)$ is approximately constant, and unsaturated, where the fractional…

We develop a model for the outer gravitationally unstable regions of accretion disks around massive black holes, for primeval or solar abundances. First we study star formation and evolution in a purely gaseous marginally unstable disk, and…

Young stellar objects (YSOs) may undergo periods of active accretion (outbursts), during which the protostellar accretion rate is temporarily enhanced by a few orders of magnitude. Whether or not these accretion outburst YSOs possess…

We mapped 12 massive protostellar candidates in the CO J=2-1 line, which in combination with Zhang et al. (2005) completes an unbiased survey of outflows for all 48 sources with l>50^o in a sample of 101 massive protostellar candidates. We…

Background: low-mass stars are the dominant product of the star formation process, and they trace star formation over the full range of environments, from isolated globules to clusters in the central molecular zone. In the past two decades,…

MHD models and the observation of accretion streamers confirmed that protostars can undergo late accretion events after the initial collapse phase. To provide better constraints, we study the evolution of stellar masses in MHD simulations…

Accretion dynamics in the forming of young stars is still object of debate because of limitations in observations and modelling. Through scaled laboratory experiments of collimated plasma accretion onto a solid in the presence of a magnetic…