Related papers: Reconstructing the cosmic evolution of the chemica…
Nuclear reactions transform atomic nuclei inside stars. This is the process of stellar nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars are reviewed. How stars manage to burn their fuel so slowly most…
The first stars ended the cosmic Dark Ages and created the first heavy elements necessary for the formation of planets and life. The properties of these stars remain uncertain, and it may be decades before individual Pop III stars are…
As building blocks of dust, rocky planets, and even complex life, the chemical elements heavier than hydrogen (H) and helium (He) - called "metals" in astronomy - play an essential role in our Universe and its evolution. Up to Fe and Ni,…
We have developed a detailed standard chemical evolution model to study the evolution of all the chemical elements up to the iron peak in the solar vicinity. We consider that the Galaxy was formed through two episodes of exponentially…
At early times the Universe was filled up with an extremely dense and hot gas. Due to the expansion it cooled below the binding energies of atoms which led to the formation of the first nuclei. In the physical environment of the…
Massive star formation exhibits an extremely rich chemistry. However, not much evolutionary details are known yet, especially at high spatial resolution. Therefore, we synthesize previously published Submillimeter Array…
Cool, evolved stars are the main source of chemical enrichment of the interstellar medium (ISM), and understanding their mass loss and structure offers a unique opportunity to study the cycle of matter in the Universe. Pulsation,…
How are the heavy elements formed? This has been a key open question in physics for decades. Recent direct detections of neutron star mergers and observations of evolved stars show signatures of chemical elements in the blue range of their…
The Milky Way nuclear star cluster (MW NSC) has been used as a template to understand the origin and evolution of galactic nuclei and the interaction of nuclear star clusters with supermassive black holes. It is the only nuclear star…
Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element abundance patterns…
Almost since the beginning, massive stars and their resultant supernovae have played a crucial role in the Universe. These objects produce tremendous amounts of energy and new, heavy elements that enrich galaxies, encourage new stars to…
The first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide…
The first stars to form in the history of the universe may have been powered by dark matter annihilation rather than by fusion. This new phase of stellar evolution may have lasted millions to billions of years. These dark stars can grow to…
We review recent theoretical results on the formation of the first stars and quasars in the universe, and emphasize related open questions. In particular, we list important differences between the star formation process at high redshifts…
People usually smile when astrophysicists assert that we are sons of the stars, but human life confirms this sentence: about 65% of the mass of our body is made up of oxygen, carbon occurs in all organic life and is the basis of organic…
Big Bang nucleosynthesis produces only light elements and the very first generation stars are thus formed from metal-free clouds. They start the production of heavy elements during their life, and enrich the interstellar medium through…
Core collapse supernovae are the leading actor in the story of the cosmic origin of the chemical elements. Existing models, which generally assume spherical symmetry and parameterize the explosion, have been able to broadly replicate the…
The recent discovery of a hyper metal-poor (HMP) star, whose metallicity Fe/H is smaller than 1/100,000 of the solar ratio, together with one earlier HMP star, has raised a challenging question if these HMP stars are the actual first…
Chemical abundances provide important clues to the evolution of galaxies. Ionized nebulae are one of the main sources of chemical abundance measurements, especially in external galaxies. Studies of H II regions have shown that the overall…
Since stellar populations enhance particular element abundances according to the yields and lifetimes of the stellar progenitors, the chemical evolution of galaxies serves as one of the key tools that allows the tracing of galaxy evolution.…