相关论文: Interstellar Ices
Context. Interstellar surface chemistry is a complex process that occurs in icy layers accumulated onto grains of different sizes. Efficiency of surface processes often depends on the immediate environment of adsorbed molecules. Aims. We…
In the denser and colder ($\leq$20 K) regions of the interstellar medium (ISM), near-infrared observations have revealed the presence of sub-micron sized dust grains covered by several layers of H\textsubscript{2}O-dominated ices and…
This paper presents Spitzer-IRS spectroscopy of the CO2 15.2 micron bending mode toward a sample of 50 embedded low-mass stars in nearby star-forming clouds, taken mostly from the ``Cores to Disks (c2d)'' Legacy program. The average…
Observations of interstellar gas-phase and solid-state species in the 2.4-200 micron range obtained with the spectrometers on board the Infrared Space Observatory are reviewed. Lines and bands due to ices, polycyclic aromatic hydrocarbons,…
The physical evolution of Young Stellar Objects (YSOs) is accompanied by an enrichment of the molecular complexity, mainly triggered by the heating and energetic processing of the astrophysical ices. In this paper, a study of how the ice…
Carbon dioxide is abundant in ice mantles of dust grains; some is found in the pure crystalline form as inferred from the double peak splitting of the bending profile at about 650 cm$^{-1}$. To study how CO$_2$ segregates into the pure form…
Context. The gas and ice-grain chemistry of the pre-stellar core L1544 has been the subject of several observations and modelling studies conducted in the past years. The chemical composition of the ice mantles reflects the environmental…
Isolated dense molecular cores are investigated to study the onset of complex organic molecule formation in interstellar ice. Sampling three cores with ongoing formation of low-mass stars (B59, B335, and L483) and one starless core (L694-2)…
(Abridged) Aims & Methods. A two-dimensional, semi-analytical model is presented that follows, for the first time, the chemical evolution from a collapsing molecular cloud (a pre-stellar core) to a protostar and circumstellar disk. The…
Mid infrared spectra provide a powerful probe of the conditions in dusty galactic nuclei. They variously contain emission features associated with star forming regions and absorptions by circumnuclear silicate dust plus ices in cold…
UV ice photodesorption is an important non-thermal desorption pathway in many interstellar environments that has been invoked to explain observations of cold molecules in disks, clouds and cloud cores. Systematic laboratory studies of the…
We report on our first results from a mid-infrared spectroscopic study of ISM features in a sample of deeply obscured ULIRG nuclei using the InfraRed Spectrograph (IRS) on the Spitzer Space Telescope. The spectra are extremely rich and…
The standard model of cosmic ray heating-induced desorption of interstellar ices is based on a continuous representation of the sporadic desorption of ice mantle components from classical (0.1 micron) dust grains. This has been re-evaluated…
We present the 1.6$-$28 $\mu$m spectra of the young protostar EC 53, obtained with JWST NIRSpec IFU and MIRI MRS during the quiescent and burst phases of its periodic brightness variations. To isolate ice absorption features, we modeled and…
CO$_2$ ice is an important reservoir of carbon and oxygen in star and planet forming regions. Together with water and CO, CO$_2$ sets the physical and chemical characteristics of interstellar icy grain mantles, including desorption and…
Context. While radiative cooling of interstellar grains is a well-known process, little detail is known about the cooling of grains with an icy mantle that contains volatile adsorbed molecules. Aims. We explore basic details for the cooling…
Starless molecular cores are natural laboratories for interstellar molecular chemistry research. The chemistry of ices in such objects was investigated with a three-phase (gas, surface, and mantle) model. We considered the center part of…
Ices are the main carriers of volatiles in protoplanetary disks and are crucial to our understanding of the chemistry that ultimately sets the organic composition of planets. The ERS program Ice Age on the JWST follows the ice evolution…
General results from a 3-5 micron spectroscopic survey of nearby low-mass young stellar objects are presented. L and M-band spectra have been obtained of \~50 low mass embedded young stars using the ISAAC spectrometer mounted on UT1-Antu at…
The relation between ices in the envelopes and disks surrounding YSOs and those in the quiescent interstellar medium is investigated. For a sample of 31 stars behind isolated dense cores, ground-based and Spitzer spectra and photometry in…