相关论文: Can DNA bases be produced during molecular cloud c…
Star clusters are formed in molecular clouds which are believed to be the birth places of most stars. From recent observational data, Lada & Lada 2003 estimated that only 4% to 7% of the clusters embedded inside molecular clouds have…
Recent observations suggest that intensive molecular cloud collision can trigger massive star/cluster formation. The most important physical process caused by the collision is a shock compression. In this paper, the influence of a shock…
When it is viewed at the scale of a base pair, DNA appears as a nonlinear lattice. Modelling its properties is a fascinating goal. The detailed experiments that can be performed on this system impose constraints on the models and can be…
Diffusion of elements in the atmosphere and envelope of a star can drastically alter its surface composition, leading to extreme chemical peculiarities. We consider the case of hot subdwarfs, where surface helium abundances range from…
Arguments are given that at least a fraction of molecular clouds may live much longer time that it is usually assumed, without the transition into diffuse atomic gas (HI). We propose that star formation in these clouds may be strongly…
We investigate chemistry in the compression layer behind the interstellar shock waves, where molecular cloud formation starts. We perform three-dimensional magnetohydrodynamics simulations of converging flows of atomic gas with shock…
We review the final stages of stellar evolution, supernova properties, and chemical yields as a function of the progenitor's mass M. (1) 8 - 10 Ms stars are super-AGB stars when the O+Ne+Mg core collapses due to electron capture. These…
We revisit the problem of the star formation timescale and the ages of molecular clouds. The apparent overabundance of star-forming molecular clouds over clouds without active star formation has been thought to indicate that molecular…
The phase diagram of a water solution of DNA and oppositely charged spherical macroions is studied. DNA winds around spheres to form beads-on-a-string complexes resembling the chromatin 10 nm fiber. At small enough concentration of spheres…
The equilibrium statistical properties of DNA denaturation bubbles are examined in detail within the framework of the Peyrard-Bishop-Dauxois model. Bubble formation in homogeneous DNA is found to depend crucially on the presence of…
Cosmic dust is an important component of the Universe, and its origin, especially at high redshifts, is still unknown. I present a simple but powerful method of assessing whether dust observed in a given galaxy could in principle have been…
Prebiotic molecules, fundamental building blocks for the origin of life, have been found in carbonaceous chondrites. The exogenous delivery of these organic molecules onto the Hadean Earth could have sparked the polymerization of the first…
Filamentary molecular clouds are recognized as primary sites for the formation of stars. Specifically, regions characterized by the overlapping point of multiple filaments, known as hub regions, often associated with active star formation.…
Modern cosmological simulations predict that the first generation of stars formed with a mass scale around 100 solar masses about 300-400 million years after the Big Bang. When the first stars reached the end of their lives, many of them…
Massive stars have a strong impact on their surroundings, in particular when they produce a core-collapse supernova at the end of their evolution. In these proceedings, we review the general evolution of massive stars and their properties…
Hydrogen cyanide (HCN) is crucial for the RNA World hypothesis, forming biomolecules essential for early life. Life likely emerged around 4 billion years ago during the early Archean Eon, a period on Earth with a fainter sun, frequent…
The cold molecular gas in contemporary galaxies is structured in discrete cloud complexes. These giant molecular clouds (GMCs), with $10^4$-$10^7$ solar masses and radii of 5-100 parsecs, are the seeds of star formation. Highlighting the…
We studied the electrical conductivity of DNA molecules with conducting atomic force microscopy as a function of the chemical nature of the substrate surfaces, the nature of the electrical contact, and the number of DNA molecules (from a…
A critical early stage for the origin of life on Earth may have involved the production of hydrogen cyanide (HCN) in a reducing, predominantly H$_2$ atmosphere. HCN is crucial for the origin of life as it is a possible precursor to several…
Analytical and numerical galaxy-formation models indicate that active galactic nuclei (AGNs) likely play a prominent role in the formation and evolution of galaxies. However, quantifying this effect requires knowledge of how the nuclear…