相关论文: Can Galactic chemical evolution explain the oxygen…
Standard stellar evolution theory is inconsistent with the observed isotopic carbon ratio, 12C/13C, in evolved stars. This theory is also inconsistent with the 3He/H abundance ratios observed in Galactic HII regions, when combined with…
We discuss the chemical pre-conditions for planet formation, in terms of gas and ice abundances in a protoplanetary disk, as function of time and position, and the resulting chemical composition and cloud properties in the atmosphere when…
In our grid of multiphase chemical evolution models (Moll\'a & D\'iaz, 2005), star formation in the disk occurs in two steps: first, molecular gas forms, and then stars are created by cloud-cloud collisions or interactions of massive stars…
Over the past decade a new generation of chemical models have included the dust in the treatment of the ISM. This major accomplishment has been spurred by the growing amounts of data on the highly obscured high-z Universe and the intriguing…
The formation of organic compounds is generally assumed to result from abiotic processes in the Solar System, with the exception of biogenic organics on Earth. Nitrogen-bearing organics are of particular interest, notably for prebiotic…
We present new mm interferometric and optical integral-field unit (IFU) observations and construct a sample of 12 E and S0 galaxies with molecular gas which have both CO and optical maps. The galaxies contain 2 x 10^7 to 5 x 10^9 M\odot of…
(Abridged) Exoplanet atmospheres are thought be built up from accretion of gas as well as pebbles and planetesimals in the midplanes of planet-forming disks. The chemical composition of this material is usually assumed to be unchanged…
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…
The outer Galaxy is characterized by a lower metallicity than regions near the Sun, suggesting differences in the formation and survival of molecules in star-forming regions. To understand chemical evolution across the Milky Way, deriving…
Recent observations of carbon, sulphur, and titanium isotopes at redshifts z~1 and in the local stellar disc and halo have opened a new window into the study of isotopic abundance patterns and the origin of the chemical elements. Using our…
Carbon monoxide (CO) is the primary tracer for interstellar clouds where stars form, yet CO has never been detected in galaxies with an Oxygen abundance relative to Hydrogen less than 20% of solar, even though such low metallicity galaxies…
The Galaxy is in continuous elemental evolution. Since new elements produced by dying stars are delivered to the interstellar medium, the formation of new enerations of stars and planetary systems is influenced by this metal enrichment. We…
Carbon-rich grains with isotopic anomalies compared to the Sun are found in primitive meteorites. They were made by stars, and carry the original stellar nucleosynthesis signature. Silicon carbide grains of Type X and C, and low-density…
The late stages of stellar evolution from asymptotic giant branch stars to planetary nebulae are now known to be an active phase of molecular synthesis. Over 80 gas-phase molecules have been detected through rotational transitions in the…
Nucleosynthetic isotope anomalies in meteorites allow distinguishing between the non-carbonaceous (NC) and carbonaceous (CC) meteorite reservoirs and show that correlated isotope anomalies exist in both reservoirs. It is debated, however,…
We study interstellar dust evolution in various environments by means of chemical evolution models for galaxies of different morphological types. We start from the formalism developed by Dwek (1998) to study dust evolution in the solar…
It is widely believed that the global baryon content and mass-to-light ratio of groups and clusters of galaxies are a fair representative of the matter mix of the universe and therefore, can be used to reliably determine the cosmic mass…
Initial conditions are set by Big bang nucleosynthesis from which we know that 90 per cent of baryons are dark and have essentially unknown chemical composition. In our own Galaxy, there are many clues from individual stars in different…
The considerable scatter of the s- and r-process elements observed in low-metallicity stars, compared to the small star to star scatter observed for the alpha elements, is an open question for the chemical evolution studies. We have…
Meteorites are classified as either non-carbonaceous- (NC) or carbonaceous (CC), representing bodies that likely formed in the inner- or outer solar system, respectively. Despite its location in the inner solar system, the Earth is thought…