Related papers: The Luminosity Problem: Testing Theories of Star F…
Class I protostars in three high-mass star-forming regions are found to have correlations among the local projected density of other Class I protostars, the summed flux from these other protostars, and the protostellar luminosity in the…
We study the formation of very metal-poor stars under protostellar radiative feedback effect. We use cosmological simulations to identify low-mass dark matter halos and star-forming gas clouds within them. We then follow protostar formation…
Developing a theory of low-mass star formation ($\sim 0.1$ to 3~M$_{\odot}$) remains one of the most elusive and important goals of theoretical astrophysics. The star-formation process is the outcome of the complex dynamics of interstellar…
The nature of the first generation of stars in the Universe remains largely unknown. Observations imply the existence of massive primordial stars early in the history of the universe, and the standard theory for the growth of cosmic…
In this last decade, our knowledge of evolutionary and structural properties of stars of different mass and chemical composition is significantly improved. This result has been achieved as a consequence of our improved capability in…
Theory predicts and observations confirm that low-mass stars (like the Sun) in their early life grow by accreting gas from the surrounding material. But for stars ~ 10 times more massive than the Sun (~10 M_sun), the powerful stellar…
There is a longstanding discussion about whether low mass stars can form from pristine gas in the early Universe. A particular point of interest is whether we can find surviving pristine stars from the first generation in our local…
How a star forms is a fundamental question in astrophysics. In the earliest stages of protostellar evolution high extinction prevents a direct study of the accretion processes and their temporal evolution. Monitoring the variations of the…
There has been remarkable progress recently in both observational and theoretical studies of galaxy formation and evolution. Largely due to a combination of deep Hubble Space Telescope imaging, Keck spectroscopy, and COBE far-IR background…
Star formation has often been studied by separating the low- and high-mass regimes with an approximate boundary at 8M_sun. While some of the outcomes of the star-formation process are different between the two regimes, it is less clear…
A model of core-clump accretion with equally likely stopping describes star formation in the dense parts of clusters, where models of isolated collapsing cores may not apply. Each core accretes at a constant rate onto its protostar, while…
Stars form from the gravitational collapse of dense molecular cloud cores. In the protostellar phase, mass accretes from the core onto a protostar, likely through an accretion disk, and it is during this phase that the initial masses of…
The mass of a protostar is calculated from the infall and dispersal of an isothermal sphere in a uniform background. For high contrast between peak and background densities and for short dispersal time t_d, the accretion is "self-limiting":…
Motivated by the long-standing "luminosity problem" in low-mass star formation whereby protostars are underluminous compared to theoretical expectations, we identify 230 protostars in 18 molecular clouds observed by two Spitzer Space…
Star formation lies at the center of a web of processes that drive cosmic evolution: generation of radiant energy, synthesis of elements, formation of planets, and development of life. Decades of observations have yielded a variety of…
The process of star formation from metal-free gas is investigated by following the evolution of accreting protostars with emphasis on the properties of massive objects. The main aim is to establish the physical processes that determine the…
The processes of star formation are fundamentally different from those of planet formation. Since the mass of a very-low-mass object alone doesn't allow us to uniquely determine its basic nature, we have to look at its other…
We describe results from a fully self-consistent three dimensional hydrodynamical simulation of the formation of one of the first stars in the Universe. Dark matter dominated pre-galactic objects form because of gravitational instability…
In star forming regions, we can observe different evolutionary stages of various objects and phenomena such as molecular clouds, protostellar jets and outflows, circumstellar disks, and protostars. However, it is difficult to directly…
Initial conditions for star formation in clusters are estimated for protostars whose masses follow the initial mass function (IMF) from 0.05 to 10 solar masses. Star-forming infall is assumed equally likely to stop at any moment, due to gas…