相关论文: Modelling the sulphur chemistry evolution in Orion…
Sulphur depletion in the interstellar medium (ISM) is a long-standing issue, as only 1% of its cosmic abundance is detected in dense molecular clouds (MCs), while it does not appear to be depleted in other environments. In addition to gas…
We investigate to what degree local physical and chemical conditions are related to the evolutionary status of various objects in star-forming media. rho Oph A displays the entire sequence of low-mass star formation in a small volume of…
Dust grains play a crucial role in the modeling of protostellar formation, particularly through their opacity and interaction with the magnetic field. The destruction of dust grains in numerical simulations is currently modeled primarily by…
Recent observations of the HDO/H$_2$O ratio toward protostars in isolated and clustered environments show an apparent dichotomy, where isolated sources show higher D/H ratios than clustered counterparts. Establishing which physical and…
This work aims to study the unexplained sulfur depletion observed toward dense clouds and protostars. We made simulation experiments of the UV-photoprocessing and sublimation of H2S and H2S:H2O ice in dense clouds and circumstellar regions,…
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…
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…
The derivation of sulphur chemical abundances in the gas-phase of star-forming galaxies is explored in this work, using the emission lines produced in these regions in the optical part of the spectrum and by means of photoionization models.…
We study the changes in physical and chemical conditions during the collapse of a pre--protostellar core, starting from initial conditions appropriate to a dense molecular cloud and proceeding to the ``completely depleted'' limit. We follow…
Sulphur is an important, volatile alpha element but its role in the Galactic chemical evolution is still uncertain. We derive the S abundances in RGB stars in three Galactic globular clusters (GC) that cover a wide metallicity range…
The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various…
As part of the first high resolution far-IR spectral survey of the Orion KL region (Lerate et al. 2006), we observed 20 CO emission lines with Jup=16 to Jup=39 (upper levels from approx 752 K to 4294 K above the ground state). Observations…
We study the impact of dust evolution in a protoplanetary disk around a T Tauri star on the disk chemical composition. For the first time we utilize a comprehensive model of dust evolution which includes growth, fragmentation and…
We present the first results of a detailed modeling of chemical and photometric evolution of galaxies including the effects of a dusty interstellar medium. A chemical evolution code follows the SF rate, the gas fraction and the metallicity,…
We study the formation of giant dense cloud complexes and of stars within them by means of SPH numerical simulations of the mildly supersonic collision of gas streams (``inflows'') in the warm neutral medium (WNM). The resulting…
Sulfur abundances are derived for a sample of ten B main-sequence star members of the Orion association. The analysis is based on LTE plane-parallel model atmospheres and non-LTE line formation theory by means of a self-consistent spectrum…
The study of the chemical evolution of glycine in the interstellar medium is one of challenging topics in astrochemistry. Here, we present the chemical modeling of glycine in hot cores using the state-of-the-art three-phase chemical model…
We have developed the first gas-grain chemical model for oxygen fractionation (also including sulphur fractionation) in dense molecular clouds, demonstrating that gas-phase chemistry generates variable oxygen fractionation levels, with a…
In the earliest phases of star-forming clouds, stable molecular species, such as CO, are important coolants in the gas phase. Depletion of these molecules on dust surfaces affects the thermal balance of molecular clouds and with that their…
In star-forming regions, molecular cloud history and dynamics set the trend in the chemical composition. Ice formation, in particular, is affected by the evolution of physical conditions, which can lead to different ice compositions within…