Related papers: The Luminosity Problem: Testing Theories of Star F…
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…
Evidence abounds that young stellar objects undergo luminous bursts of intense accretion that are short compared to the time it takes to form a star. It remains unclear how much these events contribute to the main-sequence masses of the…
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,…
The first stars in the Universe are predicted to have been much more massive than the Sun. Gravitational condensation accompanied by cooling of the primordial gas due to molecular hydrogen, yields a minimum fragmentation scale of a few…
Star formation generally proceeds inside-out, with overdense regions inside protostellar cores collapsing rapidly and progressively less dense regions following later. Consequently, a small protostar will form early in the evolution of a…
The observed star formation rate of the Milky Way can be explained by applying a metallicity-dependent factor to convert CO luminosity to molecular gas mass and a star formation efficiency per free-fall time that depends on the virial…
Star formation is a multi-scale, multi-physics problem ranging from the size scale of molecular clouds ($\sim$10s pc) down to the size scales of dense prestellar cores ($\sim$0.1 pc) that are the birth sites of stars. Several physical…
Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…
We investigate the evolution of cosmological low mass (low virial temperature) objects and the formation of the first luminous objects. First, the `cooling diagram' for low mass objects is shown. We assess the cooling rate taking into…
In an improved model of protostar mass functions (PMFs), protostars gain mass from isothermal cores in turbulent clumps. Their mass accretion rate is similar to Shu accretion at low mass, and to reduced Bondi accretion at high mass.…
Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…
A star acquires much of its mass by accreting material from a disc. Accretion is probably not continuous but episodic. We have developed a method to include the effects of episodic accretion in simulations of star formation. Episodic…
The first stars in the Universe form when chemically pristine gas heats as it falls into dark matter potential wells, cools radiatively due to the formation of molecular hydrogen, and becomes self-gravitating. We demonstrate with…
I review theoretical models of star formation and how they apply across the stellar mass spectrum. Several distinct theories are under active study for massive star formation, especially Turbulent Core Accretion, Competitive Accretion and…
The formation of low-mass protostars and especially of brown dwarfs currently are ``hot topics'' in cool star research. The talks contributed to this splinter session discussed how low in mass and how low in luminosity objects might exist,…
The process that leads to the formation and early evolution of low-mass stars is in a broad sense well understood theoretically and carefully traced observationally. The largest uncertainties in this framework reside in the poorly known…
Although fundamental for astrophysics, the processes that produce massive stars are not well understood. Large distances, high extinction, and short timescales of critical evolutionary phases make observations of these processes…
These lectures attempt to expose the most important ideas, which have been proposed to explain the formation of stars with particular emphasis on the formation of brown dwarfs and low-mass stars. We first describe the important physical…
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…
Low surface brightness regions are found not only in dwarf and ultra-diffuse galaxies, but also on the outer parts of giant spirals, or in galaxy extensions (tidal or ram-pressure tails, outflows or jets). Sometimes molecular gas is…