Related papers: Star formation thresholds and galaxy edges: why an…
Discs of gas and dust are ubiquitous around protostars. Hypothetical disc viscosity is thought to cause the gas and dust to accrete onto the star. Turbulence within the disc might be the source of this disc viscosity. However, observed…
Observations of circumstellar disks around stars as a function of stellar properties such as mass, metallicity, multiplicity, and age, provide constraints on theories concerning the formation and evolution of planetary systems. Utilizing…
As they grow, galaxies can transition from irregular/spheroidal with 'bursty' star formation histories (SFHs), to disky with smooth SFHs. But even in simulations, the direct physical cause of such transitions remains unclear. We therefore…
We analytically calculate the marginally stable surface density profile for rotational instability of protoplanetary disks. The derived profile can be utilized for considering the region in a rotating disk where radial pressure gradient…
The Lin and Pringle model (1987) of galactic disk formation postulates that if star formation proceeds on the same timescale as the viscous redistribution of mass and angular momentum in disk galaxies, then the stars attain an exponential…
Recent observations show that planet formation is already underway in young systems, when the protostar is still embedded into the molecular cloud and the accretion disc is massive. In such environments, the role of self gravity (SG) and…
We present a model using the evolution of the stellar population in a starburst galaxy to predict the crystallinity of the silicates in the interstellar medium of this galaxy. We take into account dust production in stellar ejecta, and…
We investigate the formation of planetesimals via the gravitational instability of solids that have settled to the midplane of a circumstellar disk. Vertical shear between the gas and a subdisk of solids induces turbulent mixing which…
Star formation is mainly determined by the observation of H$\alpha$ radiation which is related to the presence of short lived massive stars. Disc galaxies show a strong cutoff in H$\alpha$ radiation at a certain galactocentric distance…
We present results concerning the internal structure and kinematics of disk galaxies formed in cosmologically motivated simulations. The calculations include dark matter, gas dynamics, radiative cooling, star formation, supernova feedback…
The formation of thick stellar disks in spiral galaxies is studied. Simulations of gas-rich young galaxies show formation of internal clumps by gravitational instabilities, clump coalescence into a bulge, and disk thickening by strong…
Through the study of two absorption spectral features in the optical range (Mg2 and the 4000 A break), we find evidence for star formation in the inner regions of cooling-flow galaxies. The application of simple stellar population models…
The formation of a star is a dynamic process fed by the gravitational collapse of a molecular cloud core. Theoretical models and observations suggest that the majority of this infalling material settles into a protoplanetary disk before…
Based on simple physical and geometric assumptions, we have calculated the mean surface molecular density of spiral galaxies at the threshold between star formation induced by cloud-cloud collision and spontaneous gravitational collapse.…
This is a brief review of our understanding of the properties of the interstellar medium (ISM) in dwarf galaxies in connection to their star formation activity. What are the dominant phases of the ISM in these objects? How do the properties…
Star formation often occurs within or nearby stellar clusters. Irradiation by nearby massive stars can photoevaporate protoplanetary disks around young stars (so-called proplyds) which raises questions regarding the ability of planet…
Gravitational instability has been invoked as a possible mechanism of giant planet formation in protoplanetary disks. Here we critically revise its viability by noting that for the direct production of giant planets it is not enough for…
The collapse of interstellar gaseous clouds towards a protostar leads to the formation of accretion disks around the central star. Such disks can be dynamically stable if they settle in an axisymmetric state. In this letter, we investigate…
The relationship between the geometrical properties of stellar disks (a flatness and truncation radius) and the disk kinematics are considered for edge-on galaxies. It is shown that the observed thickness of the disks and the approximate…
We discuss star formation in the turbulent interstellar medium. We argue that morphological appearance and dynamical evolution of the gas is primarily determined by supersonic turbulence, and that stars form via a process we call…