相关论文: Can DNA bases be produced during molecular cloud c…
The Sun is thought to be formed within a star cluster. The coexistence of $^{26}{\rm Al}$-rich and $^{26}{\rm Al}$-poor calcium--aluminum-rich inclusions indicates that a direct injection of $^{26}{\rm Al}$-rich materials from a nearby…
Observations of both star-forming regions and young, gas-free stellar associations indicate that most nearby molecular clouds form stars only over a short time span before dispersal; large-scale flows in the diffuse interstellar medium have…
An attempt is made, probably for the first time, to understand the origin of the solar system in context with the evolution of the galaxy as a natural consequence of the birth of several generations of stellar clusters. The galaxy is…
We study the evolution of molecular hydrogen on the grain surfaces and in the gas phase using both the rate equation (which tracks the average number of molecules) and the master equation (which tracks the expectation values of molecules).…
Observations suggest that star formation occurs in only one or two crossing times for a range of scales spanning a factor of 1000. These observations include (1) measurements of embedded cluster ages in comparison with the cloud core…
Giant molecular clouds (GMCs) and their stellar offspring are the building blocks of galaxies. The physical characteristics of GMCs and their evolution are tightly connected to galaxy evolution. The macroscopic properties of the…
Most young stars in nearby molecular clouds have estimated ages of 1-2 Myr, suggesting that star formation is rapid. However, small numbers of stars in these regions with inferred ages of >= 5-10 Myr have been cited to argue that star…
We investigate molecular evolution in a star-forming core that is initially a hydrostatic starless core and collapses to form a low-mass protostar. The results of a one-dimensional radiation-hydrodynamics calculation are adopted as a…
Understanding the chemical evolution in star-forming cores is a necessary pre-condition to correctly assess physical conditions when using molecular emission. We follow the evolution of chemistry and molecular line profiles through the…
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 proto-clusters have survived. Many factors could…
The building blocks of life, amino acids and nucleobases, are believed to have been synthesized in the extreme conditions that prevail in space starting from simple molecules containing hydrogen, carbon, oxygen and nitrogen. However, the…
In the redshift range 100<(1+z)<137, the cosmic microwave background (CMB) had a temperature of 273-373K (0-100 degrees Celsius), allowing early rocky planets (if any existed) to have liquid water chemistry on their surface and be…
Our Sun, like all stars, formed within a cold molecular cloud. Astronomical observations and theory provide considerable detail into this process. Yet cosmochemical observations of short lived radionuclides in primitive meteorites, in…
Complex organic molecules (COMs) are thought to be the precursors of pre-biotic molecules and are observed in many protostellar sources. For this paper we studied the formation of COMs during star formation and their evolution in the…
To characterize the thermodynamical equilibrium of DNA chains interacting with a solution of non-specific binding proteins, a Flory-Huggins free energy model was implemented. We explored the dependence on DNA and protein concentrations of…
During its early evolution, the hot, dense Universe provided a laboratory for probing fundamental physics at high energies. By studying the relics from those early epochs, such as the light elements synthesized during primordial…
We have investigated chemical evolution in the young universe by analysing the detailed chemical enrichment pattern of a metal-rich galaxy at high redshift. The recent detection of over 20 elements in the gas-phase of a damped Lyman-alpha…
It is suggested that life originated in a three-step process referred to as the jigsaw model. RNA, proteins, or similar organic molecules polymerized in a dehydrated carbon-rich environment, on surfaces in a carbon-rich environment, or in…
The effective DNA-DNA interaction force is calculated by computer simulations with explicit tetravalent counterions and monovalent salt. For overcharged DNA molecules, the interaction force shows a double-minimum structure. The positions…
The RNA World hypothesis predicts that self-replicating RNAs evolved before DNA genomes and coded proteins. Despite widespread support for the RNA World, self-replicating RNAs have yet to be identified in a natural context, leaving a key…