Related papers: Nuclear burning rates and population II stellar mo…
NIR high angular resolution speckle imaging and imaging spectroscopy of the nuclear region (10'' ~ 840pc) of the Seyfert1 galaxy NGC3227 are presented. A nuclear stellar cluster is slightly resolved in the J and H band with increasing…
We report the first star formation history study of the Milky Way's nuclear star cluster (NSC) that includes observational constraints from a large sample of stellar metallicity measurements. These metallicity measurements were obtained…
The formation and evolution of binaries which contain two neutron stars or a neutron star with a black hole are discussed in detail. The evolution of the distributions in orbital period and eccentricity for neutron star binaries are studied…
Effective values for the key helium burning reaction rates, triple-alpha and 12C(alpha,gamma)16O, are obtained by adjusting their strengths so as to obtain the best match with the solar abundance pattern of isotopes uniquely or…
Recent precise determinations of the primordial He-abundance (Y_p) from cosmic microwave background (CMB) analyses and cosmological nucleosynthesis computations, provide Y_p=0.248$\pm$0.001. On the other hand, recent works on the initial…
We present yields from stars of mass in the range Mo<M<8Mo of metallicities Z=0.0003 and Z=0.008, thus encompassing the chemistry of low- and high-Z Globular Clusters. The yields are based on full evolutionary computations, following the…
Resolution of nearby giant HII regions into their stellar and nebular constituents provides fundamental insights for interpreting more distant and powerful starburst activity. The following summarizes recent advances in our understanding of…
We report here on two complementary population synthesis studies which relate directly to the formation and evolution of neutron star binaries in globular clusters. In the first, we compute the probability of retaining neutron stars in…
A variation of the fundamental constants is expected to affect the thermonuclear rates important for stellar nucleosynthesis. In particular, because of the very small resonant energies of Be8 and C12, the triple $\alpha$ process is…
We provide a set of stellar evolution and nucleosynthesis calculations that applies established physics assumptions simultaneously to low- and intermediate-mass and massive star models. Our goal is to provide an internally consistent and…
Neutron stars in mass-transferring binaries are accreting the hydrogen and helium rich matter from the surfaces of their companions. This article simply explains the physics associated with how that material eventually fuses to form heavier…
Models of stellar structure and evolution can be constrained by measuring accurate parameters of detached eclipsing binaries in open clusters. Multiple binary stars provide the means to determine helium abundances in these old stellar…
The main sequence turnoff luminosity is the best stellar `clock' which can be used to determine the absolute ages of globular clusters. This is due to the fact that it is generally assumed that the luminosity and lifetimes of main sequence…
Full evolutionary models have been built to follow the phases of asymptotic giant branch evolution with mass loss for metal mass fractions from Z=0.0002 to Z=0.004. For the first time, we find that temperatures close to or even larger than…
Runaway thermonuclear burning of a layer of accumulated fuel on the surface of a compact star provides a brief but intense display of stellar nuclear processes. For neutron stars accreting from a binary companion, these events manifest as…
One of the largest uncertainties in stellar evolutionary computations is the accuracy of the considered reaction rates. The 12C(alpha,gamma)16O reaction is particularly important for the study of low- and intermediate-mass stars as it…
Recent observations with the Hubble Space Telescope (HST) have revealed that a large fraction of late-type (Sc and later) spiral galaxies harbor a bright, compact stellar cluster in their dynamical centers. Statistics of the mass, age, and…
We have performed a census of the UV-bright population in 78 globular clusters using wide-field UV telescopes. This population includes a variety of phases of post-horizontal branch (HB) evolution, including hot post-asymptotic giant branch…
The luminosity evolution of stars with highly condensed cores surrounded by nuclear-burning shell(s) is analytically investigated with the aid of homology relations. With respect to earlier works using a similar approach (e.g. Refsdal &…
We calculate the theoretical event rate of gamma-ray bursts (GRBs) from the collapse of massive first-generation (Population III; Pop III) stars. The Pop III GRBs could be super-energetic with the isotropic energy up to $E_{\rm iso} \gtrsim…