Related papers: Adenine Abundance in a Collapsing Molecular Cloud
We present the second part of an optical spectroscopic study of planetary nebulae in the LMC and SMC. The first paper, Leisy & Dennefeld (1996), discussed the CNO cycle for those objects where C abundances were available. In this paper we…
The relative chemical abundances between CI meteorites and the solar photosphere exhibit a significant trend with condensation temperature. A trend with condensation temperature is also seen when the solar photospheric abundances are…
We investigate the condition for the formation of micron-sized grains in dense cores of molecular clouds. This is motivated by the detection of the mid-infrared emission from deep inside a number of dense cores, the so-called `coreshine,'…
It is now well-established that the elemental abundance patterns of stars holds key clues not only to their formation but also to the assembly histories of galaxies. One of the most exciting possibilities is the use of stellar abundance…
A supersonic cloud-cloud collision produces a shock-compressed layer which leads to formation of high-mass stars via gravitational instability. We carried out a detailed analysis of the layer by using the numerical simulations of…
The Perseus Cluster has been precisely measured by the legacy Hitomi telescope on the Si-group (Si, S, Ar, Ca) and Fe-group elements (Cr, Mn, Ni). These element abundance ratios provide insight into the typical behaviour of supernovae. In…
Although they are only minor constituents of the interstellar medium, halogen-containing molecules are of special interest because of their unique thermochemistry. Here, we present a theoretical study of the chemistry of interstellar…
We selected 90 massive star-forming clumps with strong N2H+, HCO+, HCN, and HNC emission from the Millimetre Astronomy Legacy Team 90 GHz survey. We obtained Herschel data for all 90 sources and NRAO VLA Sky Survey data for 51 of them. We…
Stellar abundances for a large number of stars are key information for the study of Galactic formation history. Large spectroscopic surveys such as DESI and LAMOST take median-to-low resolution ($R\lesssim5000$) spectra in the full optical…
The abundance evolution of interstellar dust species originating from stellar sources and from condensation in molecular clouds in the local interstellar medium of the Milky Way is studied and the input of dust material to the Solar System…
A new type of artificial molecule is proposed, which consists of coupled defect atoms in photonic crystals, named as photonic molecule. Within the major band gap, the photonic molecule confines the resonant modes that are closely analogous…
We explore the origin of fast molecular outflows that have been observed in Active Galactic Nuclei (AGN). Previous numerical studies have shown that it is difficult to create such an outflow by accelerating existing molecular clouds in the…
The generation of a kination-dominated phase by a quintessential exponential model is investigated and the parameters of the model are restricted so that a number of observational constraints (originating from nucleosynthesis, the present…
A simple theory for the chemical enrichment of the Galaxy which takes into account the effects of spiral arms on heavy elements output was developed. In the framework of the model with the corotation close to the position of the Sun in the…
Understanding stellar composition is fundamental not only to our comprehension of the galaxy, especially chemical evolution, but it can also shed light on the interior structure and mineralogy of exoplanets, which are formed from the same…
The isothermal gravitational collapse and fragmentation of a molecular cloud region and the subsequent formation of a protostellar cluster is investigated numerically. The clump mass spectrum which forms during the fragmentation phase can…
Based on high-resolution spectral observations for a sample of very metal-poor stars, we investigate how well stellar chemical abundances can be derived with available theoretical methods and computational tools.
Studies of element abundances in stars are of fundamental interest for their impact in a wide astrophysical context, from our understanding of galactic chemistry and its evolution, to their effect on models of stellar interiors, to the…
It is now well known that a primordial chemistry, involving light elements produced during the nucleosynthesis period, might develop during the hydrogen post-recombination era. In particular, molecular ions and primordial molecules such as…
We review recent advances in the analytical and numerical modeling of the star formation rate in molecular clouds and discuss the available observational constraints. We focus on molecular clouds as the fundamental star formation sites,…