Dutch Astrochemistry Network – II

Publication: Netherlands Organisation for Scientific Research (NWO) NWO Domain Science E: [email protected] W: www.nwo.nl/astrochemistry April 2018 Dutch Astrochemistry Network – II Netherlands Organisation for Scientific Research Colophon Text: Dutch Astrochemistry Community Coordination and editing: Sebastiaan de Vet Design: Christy Renard (Communications) Printed by: Ipskamp printing On the cover: Detail of the Galactic Plane visible from the southern hemisphere imaged during the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The APEX data, at a wavelength of 0.87 millimetres, shows up in red and the background blue image was imaged at shorter infrared wavelengths by the NASA Spitzer Space Telescope as part of the GLIMPSE survey. The fainter extended red structures come from complementary observations made by ESA’s Planck satellite. Credits: ESO/APEX/ATLASGAL consortium/NASA/ GLIMPSE consortium/ESA/Planck Dutch Astrochemistry Network – II The Hague, April 2018 Netherlands Organisation for Scientific Research 2 Figure 1 Illustration of the lifecycle of molecules in the interstellar medium. Chemical processes take place at every stage in this process – from the birth of molecules in circumstellar shells, their passing through the physical gauntlet of the interstellar medium ultimately fuelling star and planet formation – and this controls the organic inventory of planetary systems. Preface In 2010, the Netherlands Organisation for Scientific Research (NWO) funded the Dutch Astrochemistry Network as a coherent and integrated research program in the physics and chemistry of molecules in space involving all the major players in this field in the Netherlands. DAN-II is a continuation of this highly successful program. Dutch researchers are very active in astronomical observations and astrophysical modelling of the molecular Universe, in laboratory studies on the spectroscopic properties and excitation rates of astronomically relevant species, and in characterizing the surfaces of materials of astronomical relevance and the reactions thereon using experimental and quantum-chemical tools. 3 Astrochemistry The origin and evolution of the molecular universe starts with the injection of material – much of it in molecular form – by stars in the later stages of their life. Subsequently, this material is processed in the interstellar medium by the prevalent ultraviolet radiation fields, energetic particles, and strong shocks. During their sojourn in the interstellar medium of galaxies, simple molecules and atoms combine to form larger species, they condense into ices where further chemical processing occurs in a bottom-up process. At the same time, complex molecules formed in stellar ejecta are broken down to smaller species by strong UV fields in a top-down fashion. Eventually, these simple and complex molecules can end up in the comets, asteroids, and planets of young protoplanetary disks. This ‘chemical dance’ of the elements leads to a rich and varied chemical inventory in the interstellar medium of galaxies. A major goal of 4 astrochemistry is to understand this chemical diversity under the extreme conditions of space. Over the last 10 years, the reigning paradigm – life on Earth is unique – has shifted towards the opinion that life could be a common characteristic of the Universe. We have discovered that there are billions and billions of planets in our own Milky Way alone. Furthermore, it has been found that life started really very quickly on the early Earth and that life in the form of extremophiles can bloom under very adverse conditions on Earth. As a result, the key question has shifted from ‘Are we alone?’ to ‘How can we best search for the biomarkers of life on other planets in our Solar system and beyond?’. Life as we know it is largely chemical in nature. Therefore, studies on the origin of life start with astrochemistry and the quest to understand the raw materials of life produced by chemical evolution in space and how these are delivered to new planetary systems. During their evolution in space, molecules exert a direct influence on their environment. Molecules dominate the cooling of gas inside dense molecular clouds. Molecules also control the ionization balance in such environments and thereby the coupling of magnetic fields to the gas. Through this influence on the forces supporting clouds against gravity, molecules will affect the process of star formation. Large molecules are also thought to be a major contributor to the heating of diffuse atomic gas in the interstellar medium. Thereby they affect the physical conditions in such environments and the phase structure of the interstellar medium, which sets the stage for the star formation process. Molecules provide also key probes of the Universe. Molecules possess a myriad of electronic, vibrational, and rotational levels whose excitation is sensitive to the local physical conditions over a wide range of astrophysically relevant densities and temperatures. Molecular abundances are also sensitive to the local physical conditions. Hence, molecules provide a sensitive tool to study the dynamics and the physical and chemical conditions in a wide range of objects at scales ranging from protoplanetary systems to galactic 5 and extragalactic scale-sizes. Molecules are directly interwoven into the fabric of the universe. They are an important component of the Universe and play a central role in many key processes that dominate the structure and evolution of galaxies. Understanding the origin and evolution of interstellar and circumstellar molecules is therefore a fundamental goal of modern astrophysics. Likewise, developing molecules as an astronomical tool to study the physical conditions and dynamics of a wide variety of objects in the Universe will be of key importance for astronomy in the coming decade. Furthermore, understanding the organic inventory of newly forming planetary systems, in particular in the habitable zone, may provide deep insight in the starting point of life in the Universe. National and international context Progress in astrochemistry is very much driven by new astronomy missions and the new views of the Universe that they open up. The Atacama Large Millimeter/submillimeter Array (ALMA) has become operational in 2013, allowing astronomers and astrochemists to study molecules in space in the sub- millimetre wavelength range. ALMA combines high sensitivity and high angular resolution, allowing revolutionary images of molecules in different environments to be made and resolving chemically different zones down to scales of a few astronomical units. The project benefits from a strong Dutch involvement. The Band 9 (602-720 GHz) receivers were built by the Netherlands Research School for Astronomy (NOVA). The Band 5 (162-211 GHz) receivers are currently also being produced by NOVA and will become operational during the DAN-II period. Over the last decade, the Spitzer Space Telescope and the Herschel Space Observatory, launched by the National Aeronautics and Space Agency (NASA) in 2003 and the European Space Agency (ESA) in 2009, respectively, have opened up the mid- and far-infrared sky for detailed spectroscopic studies of molecules. In 2020, NASA foresees the launch of the James Webb Space Telescope (JWST), a 6.5 meter telescope which promises even higher spectral & spatial resolution and sensitivity at mid-IR wavelengths. Indeed, the Mid InfraRed Instrument (MIRI) and the Near-InfraRed Spectrograph (NIRSPEC) will allow, for the first time, mid-infrared spectral 7 images to be made at sub-arcsecond resolution. This wavelength range is spectroscopically very rich and contains unique astrochemically relevant probes, including H2 and HD pure rotational lines, molecular rotation-vibration and pure rotation lines from small molecules (e.g., C2H2, CO2, HCN, NH3, SO2, H2O and OH), vibrational bands of PAHs and fullerenes, and vibrational bands of many ice components. NOVA is responsible for the design and building of the Spectrometer Main Optics Module (SMO) of MIRI. With these observatories, astrochemistry is poised to tackle key questions in astronomy; in particular, the distribution of organic material in the habitable zone of planet-forming disks around young stars and the processes that play a role in their origin and evolution. In the more distant future, these results feed into preparation for science with the METIS instrument for the Extremely Large Telescope (ELT), in which NOVA has the PI role. Over the last few years, new methods in physical chemistry have been developed that carry the promise of opening up new avenues of research in astrochemistry. Various chemistry and molecular physics groups in the Netherlands are very active in this arena. These new physical chemistry methods include, in particular, the development of new numerical methods and software for fast calculation of inelastic collisional cross sections, including systems with a deep potential well. In addition, (cooled) ion traps allow, for the first time, the study of the photophysics and characteristics of large molecules and their fragmentation products. Such studies also benefit from newly developed sensitive state-selective detection techniques including IR-UV ion-dip schemes coupled with molecular beam and resonance- enhanced multiphoton ionization techniques combined with cavity-ringdown spectroscopy and velocity map imaging. The development of unique capabilities in performing collision experiments using molecular state cooling and manipulation techniques

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