Related papers: The Spitzer ice legacy: Ice evolution from cores t…
Water is the main component of interstellar ice mantles, is abundant in the solar system and is a crucial ingredient for life. The formation of this molecule in the interstellar medium cannot be explained by gas-phase chemistry only and its…
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…
Ice-coated dust grains provide the main reservoir of volatiles that play an important role in planet formation processes and may become incorporated into planetary atmospheres. However, due to observational challenges, the ice abundance…
H2O is the most abundant component of astrophysical ices. In most lines of sight it is not possible to fit both the H2O 3 um stretching, the 6 um bending and the 13 um libration band intensities with a single pure H2O spectrum. Recent…
Solar and extrasolar comets and extrasolar planets are the subject of numerous studies in order to determine their chemical composition and internal structure. In the case of planetesimals, their compositions are important as they govern in…
(Abridged) JWST observations have measured the ice composition toward two highly-extinguished field stars in the Chamaeleon I cloud. The observed extinction excess on the long-wavelength side of the H2O ice band at 3 micron has been…
The HDO/H2O ratio is a powerful diagnostic to understand the evolution of water from the first stages of star formation to the formation of planets and comets. Our aim is to determine precisely the abundance distribution of HDO towards the…
CONTEXT: [ABRIDGED]. For the Milky Way bulge, there are currently essentially no measurements of carbon in un-evolved stars, hampering our abilities to properly compare Galactic chemical evolution models to observational data for this still…
We present new observations of the CB130 region, composed of three separate cores. Using the \textit{Spitzer Space Telescope} we detected a Class 0 and a Class II object in one of these, CB130-1. The observed photometric data from…
Planet formation is strongly influenced by the composition and distribution of volatiles within protoplanetary disks. With JWST, it is now possible to obtain direct observational constraints on disk ices, as recently demonstrated by the…
There are two major theoretical issues for the star formation law (the relation between the surface densities of molecular gas and star formation rate on a galaxy scale): (i) At low metallicity, it is not obvious that star-forming regions…
We present Spitzer IRS spectra of four carbon stars located in the Galactic Halo and the thick disc. The spectra display typical features of carbon stars with SiC dust emission and C$_2$H$_2$ molecular absorption. Dust radiative transfer…
Protoplanetary disks are thought to be the birth places of planetary systems. The formation and the subsequent evolution of protoplanetary disks are regulated by the star formation process, which begins with the collapse of a cloud core to…
Hot molecular cores (HMCs) are intermediate stages of high-mass star formation and are also known for their rich emission line spectra at (sub-)mm wavebands. The observed spectral feature of HMCs such as total number of emission lines and…
Context: Chemical models of dense cloud cores often utilize the so-called pseudo-time-dependent approximation, in which the physical conditions are held fixed and uniform as the chemistry occurs. In this approximation, the initial…
(Abridged) We present evidence that low-mass starless cores, the simplest units of star formation, are systematically differentiated in their chemical composition. Molecules including CO and CS almost vanish near the core centers, where the…
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…
The gas-phase CO abundance (relative to hydrogen) in protoplanetary disks decreases by up to 2 orders of magnitude from its ISM value ${\sim}10^{-4}$, even after accounting for freeze-out and photo-dissociation. Previous studies have shown…
Context: Diffusion of species on the dust surface is a key process for determining the chemical composition of interstellar ices. On the dust surface, adsorbed species diffuse from one potential well to another and react with other adsorbed…
It is reasonable to assume that the structure of a planet and the interior distribution of its components are determined by its formation history. We thus follow the growth of a planet from a small embryo through its subsequent evolution.…