Related papers: Synthesizing Deuterium in Incipient Pop II Stars
The prejudice against baryon isocurvature models is primarily because of their inconsistency with early universe light element nucleosynthesis results. We propose that incipient low metallicity (Pop II) star forming regions can be expected…
We describe how star formation is expected to proceed in the early metal-free Universe, focusing on the very first generations of stars. We then discuss how the star formation process may change as the effects of metallicity, external…
We discuss the cosmological significance of the transition from the Pop III to Pop II mode of star formation in the early universe, and when and how it may occur in primordial galaxies. Observations that could detect this transition include…
We present a case for Cosmological Nucleosynthesis in an FRW universe in which the scale factor expands linearly with time: $a(t) \sim t$. It is demonstrated that adequate amount of $^4He$ requires a baryon density that saturates mass…
(Abridged) Estimates of the interstellar deuterium abundance span a wide range of values. Here we study the evolution of deuterium in the framework of successful models for the chemical evolution of the Milky Way able to reproduce the…
We investigate the impact of an early population of massive stars on their surroundings. Dissociation of molecular hydrogen by strong UV emission from such stars is expected to produce a global transition in the cooling mechanism of…
Metals from Population III (Pop III) supernovae led to the formation of less massive Pop II stars in the early universe, altering the course of evolution of primeval galaxies and cosmological reionization. There are a variety of scenarios…
Despite extensive search efforts, direct observations of the first (Pop III) stars have not yet succeeded. Theoretical studies have suggested that late Pop III star formation is still possible in pristine clouds of high-mass galaxies,…
We investigate the transition from primordial Population III (Pop III) star formation to normal Pop II star formation in the first galaxies using new cosmological hydrodynamic simulations. We find that while the first stars seed their host…
It is widely believed that the cosmic baryon density may be obtained by inferring deuterium abundances in low-metallicity quasar absorption line systems. The implicit assumptions which enter this argument are critically assessed. In…
UltraCompact HII regions are signposts of high mass star formation. Since high-mass star formation occurs in clusters, one expects to find even earlier phases of massive star formation in the vicinity of UltraCompact HII regions. Here, we…
Galactic destruction of primordial deuterium is inevitably linked through star formation to the chemical evolution of the Galaxy. The relatively high present gas content and low metallicity suggest only modest D-destruction. In concert with…
Observational constraints on the primordial lithium abundance are important for the evaluation of the baryonic density of the universe. Its precise determination however suffers from uncertainties due to the possible depletion of this…
Our current understanding of the chemical evolution of the Universe is that a first generation of stars was formed out of primordial material, completely devoid of metals (Pop III stars). This first population of stars comprised massive…
In both stars and in the early universe, the production of deuterium is the first step on the way to producing heavier nuclei. If the strong force were slightly weaker, deuterium would not be stable, and many authors have noted that…
From studying the cosmic microwave background, we know our Universe started out very simple. It was by and large homogeneous and isotropic, with small fluctuations that can be described by linear perturbation theory. In stark contrast, the…
Several planets have recently been discovered around old metal-poor stars, implying that these planets are also old, formed in the early Universe. The canonical theory suggests that the conditions for their formation could not have existed…
While theoretical computations of the lithium abundances in Pop II stars predict variations from star to star, the most recent observations confirm the existence of a "lithium plateau" with no abundance dispersion. This apparent paradox has…
We model Pop III star formation in different FUV and X-ray backgrounds, including radiation feedback from protostars. We confirm previous results that a moderate X-ray background increases the number of Pop III systems per unit cosmological…
We propose a semi-analytic model that is developed to understand the cosmological evolution of the mean metallicity in the Universe. In particular, we study the contributions of Population III (Pop III) and Population II (Pop II) stars to…