Resolved emission from gas-phase methanol can reveal the abundance and distribution of the comet-forming ice reservoir in protoplanetary disks. ALMA Cycle 4 observations of four transitions of gas-phase methanol in TW Hya allow the first model-independent determination of the rotational temperature of methanol in a prototoplanetary disk. The data confirm that the methanol is rotationally cold (Trot < 50 K), and well constrain the column density to 2 × 1012 cm−2. Astrochemical models will constrain the chemical origin of methanol in TW Hya.

Dust particles covered by icy mantles play a crucial role in the formation of molecules in the Interstellar Medium (ISM). These icy mantles are mainly composed of water but many other chemical species are also contained in these ices. These compounds can diffuse and meet each other to react. It is through these surface reactions that new saturated species are formed. Photodissociation reactions are also thought to play a crucial role in the formation of radical species. Complex organic molecules are formed through an intricated network of photodissociation and surface reactions.

Both type of reactions release energy. Surface reactions are typically exothermic by a few eV, whereas photodissociation reactions are triggered by the absorption of a UV photon, resulting in the formation of highly excited products. The excited reaction products can apply this energy for desorption or diffusion, making products more mobile than predicted when considering only thermal hopping. The energy could further lead to annealing or deformation of the ice structure.

Here we would like to quantify the relative importance of these different energy dissipation routes. For this we performed thousands of Molecular Dynamics simulations for three different species (CO2, H2O and CH4) on top of a water ice surface. We consider different types of excitation such as translational, rotational, and/or vibrational excitation. The applied substrate is an amorphous solid water surface (ASW).

High-resolution stellar spectra are important tools for studying the chemical evolution of the Milky Way Galaxy, tracing the origin of chemical elements, and characterizing planetary host stars. Large amounts of data have been accumulating, in particular in the optical and infrared wavelength regions. The observed spectral lines are interpreted using model spectra that are calculated based on transition data for numerous species, in particular neutral and singly ionized atoms. We rely heavily on the continuous activities of laboratory astrophysics groups that produce high-quality experimental and theoretical atomic data for the relevant transitions. We give examples for the precision with which the chemical composition of stars observed by different surveys can be determined, and discuss future needs from laboratory astrophysics.

We present ALMA observations of four different molecular species in showcasing their potential as tracers of physical and chemical conditions in planet forming Herbig Ae disks.

The Wootton Center for Astrophysical Plasma Properties (WCAPP) is a new center focusing on the spectroscopic properties of stars and accretion disks using “at-parameter” experiments. Currently, these experiments use the X-ray output of the Z machine at Sandia National Laboratories — the largest X-ray source in the world — to heat plasmas to the same conditions (temperature, density, and radiation environment) as those observed in astronomical objects. The experiments include measuring (1) density-dependent opacities of iron-peak elements at solar interior conditions, (2) spectral lines of low-Z elements at white dwarf photospheric conditions, (3) atomic population kinetics of neon in a radiation-dominated environment, and (4) resonant Auger destruction (RAD) of silicon at conditions found in accretion disks around supermassive black holes. In particular, we report on recent results of our experiments involving helium at white dwarf photospheric conditions. We present results showing disagreement between inferred electron densities using the Hβ line and the He I 5876 Å line, most likely indicating incompleteness in our modeling of this helium line.

The pore structure of vapour deposited ASW is poorly understood, despite its importance to fundamental processes such as grain chemistry, cooling of star forming regions, and planet formation. We studied structural changes of vapour deposited D2O on intra-molecular to 30 nm length scales at temperatures ranging from 18 to 180 K and observed enhanced mobility from 100 to 150 K. An Arrhenius type model describes the loss of surface area and porosity with a common set of kinetic parameters. The low activation energy (428 K) is commensurate with van der Waals forces between nm-scale substructures in the ice. Our findings imply that water porosity will always change with time, even at low temperatures.

Accurate atomic data for line wavelengths, energy levels, line broadening such as hyperfine structure and isotope structure, and f-values, particularly for the line rich iron group elements, are needed for stellar astrophysics applications, and examples of recent measurements are given. These atomic data are essential for determination of elemental abundances in astronomical objects. With modern facilities, telescopes and spectrographs, access to underexplored regions (IR, UV, VUV), and improved stellar atmosphere models (3D, NLTE), and extremely large datasets, astronomers are tackling problems ranging from studying Galactic chemical evolution, to low mass stars and exoplanets. Such advances require improved accuracy and completeness of the atomic database for analyses of astrophysical spectra.

The surfaces of most of the atmosphereless solar system bodies are referred to as regolith or layers of usually loosely connected fragmentary debris, produced by meteorite impacts. Measurement of light scattered from such surfaces provide information about the composition and structure of the surface. In the present work, the effect of porosity and particle size, on reflectance is studied for regolith like samples. For modelling the experimental data Hapke 2008 is used and found to be in good agreement with laboratory data. From the present study, it can be concluded that the physical properties of a regolith, such as porosity, particle size etc are effectively represented by albedo.

Underground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors were commissioned. JUNA plans to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. At the first period, JUNA aims at the direct measurements of 25Mg(p,γ)26 Al, 19F(p,α) 16 O, 13C(α, n) 16O and 12C(α,γ) 16O near the Gamow window. The current progress of JUNA will be given.

Cyclopropenylidene,, is a simple hydrocarbon, ubiquitous in astrophysical gases, and possessing a permanent electric dipole moment. Its readily observed multifrequency rotational transitions make it an excellent probe for the physics and history of interstellar matter. The collisional properties of with He are presented here. We computed the full Potential Energy Surfaces, and we perform quantum scattering in order to provide rates of quenching and excitation for low to medium temperature regimes. We discuss issues with the validity of the usual Local Thermodynamical Equilibrium assumption, and also the intricacies of the spectroscopy of an asymmetric top. We present the wide range of actual critical densities, as recently observed.

The James Webb Space Telescope (JWST) is expected to be launched in 2021. The JWST’s science instruments will provide high quality spectra acquired in the line of sight to young stellar objects whose interpretation will require a robust database of laboratory data. With this in mind, an experimental work is in progress in the Laboratory for Experimental Astrophysics in Catania to study the profile (shape, width, and peak position) of the main infrared bands of molecular species expected to be present in icy grain mantles. Our study also takes into account the modifications induced on icy samples by low-energy cosmic ray bombardment and by thermal processing. Here we present some recent results on deuterium hydrogen monoxide (HDO), N-bearing species, and carbon dioxide (CO2).

The multi-photon photodissociation (MPD) action spectrum of the coronene cation $$({{\rm{C}}_{24}}{\rm{H}}_{12}^ + )$$ has been measured as a function of storage time up to 60 s in the cryogenic electrostatic storage ring DESIREE. These measurements reveal not only the intrinsic absorption profile of isolated coronene cations, but also the rate at which hot-band absorptions are quenched by radiative cooling. The cooling rate is interpreted using a Simple Harmonic Cascade model of infrared vibrational emission.

Photoionized outflows in active galactic nuclei (AGNs) are thought to influence their circumnuclear and host galactic environment. However, the distance of the outflow with respect to the black hole is poorly constrained, which limits our understanding of the kinetic power by the outflow. Therefore, the impact of AGN outflows on their host galaxies is uncertain. If the density of the outflow is known, its distance can be derived. Density measurement via variability studies and density sensitive lines have been used, albeit not very effective in the X-ray band. Good measurements are rather demanding or challenging for the current generation of (grating) spectrometers. The next generation of spectrometers will certainly provide data with better quality and large quantity, leading to tight constraints on the location and the kinetic power of AGN outflows. This contribution summarizes the state-of-the-art in this field.

The rate coefficients, k(T= 11.7 – 64.4 K), for the gas-phase reaction between OH radicals and acetone, CH3C(O) CH3, have been measured using the pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) technique, the most suitable one to cool down gases below the freezing point without gas condensation. The experimental k(T) was found to increase as temperature was lowered and is several orders of magnitude higher for low temperature than k(300 K). No pressure dependence of k(20 K) and k(64 K) was observed, while k(50 K) at the largest gas density is twice higher than the average values found at lower gas densities. The obtained values of k(11.7 K) and k(21.1 K) were 2.45’10-10 and 1.39’10-10 cm3 molecule-1 s-1, respectively.

Experimental data showing superhydrogenation of neutral polycyclic aromatic hydrocarbons (PAHs) coronene, pentacene and pentacenequinone is presented. PAH monolayers were prepared on a highly oriented pyrolytic graphite surface and subsequently exposed to a beam of atomic hydrogen. The superhydrogenated PAH species were examined via temperature programmed desorption measurements. Stable intermediate superhydrogenation degrees as well as fully superhydrogenated species are observed and the initial reaction cross section for coronene has been determined.

HD 163296 is a young star surrounded by a planet-forming disk that shows clear signatures of dust gaps and rings; likely an indication of ongoing planet formation. We use the radiation thermochemical disk code ProDiMo to investigate the impact of dust/gas gaps on the temperature, chemistry and observables. Furthermore, we model high spatial resolution gas and dust observation of HD 163296 (ALMA/DSHARP). Our first results indicate that features in the observed radial intensity profile of the 12CO line are a consequence of the dust gaps and do not require gas depletion. Those preliminary results indicate that self-consistent modelling of the gas (chemistry, heating/cooling) and dust is necessary to accurately infer the degree of gas depletion within dust gaps. Such information is crucial to understand the processes that generate the disk substructure and their relation to planet formation.

In cosmic environments, polycyclic aromatic hydrocarbons (PAHs) strongly interact with vacuum ultraviolet (VUV) photons emitted by young stars. Trapped PAH cations ranging in size from 30 to 48 carbon atoms were irradiated by tunable synchrotron light (DESIRS beamline at SOLEIL). Their ionization and dissociation cross sections were determined and compared with TD-DFT computed photoabsorption cross sections. Evidence for radiative cooling is reported.

Spectra of exoplanets, cool stars and brown dwarfs contain features due to molecular absorptions. Modelling these requires extensive line lists which are provided by the ExoMol project. Here we report on current progress and future prospects for the project.

The aim of this work is to understand the stability and investigate the chemical evolution of formamide ice due to thermal hydrogenation at simulated interstellar conditions.

Amorphous Mg-Fe silicates are produced from microwave-dried sol-gels and their thermal crystallisation is studied via in situ synchrotron X-ray powder diffraction. Mg-pyroxene crystallised to forsterite, enstatite and cristobalite. The inclusion of 10% Fe formed only forsterite at much higher temperature, while pure Mg-olivine crystallised at a lower temperature than Mg-pyroxene. Cristobalite is observed as a high-temperature crystallite in the pure-Mg compositions. Crystallisation activation energies are derived and discussed in relation to protoplanetary disks.