ERC FUNDED PROJECTS

ASTROFLOW aims to make ground-breaking progress in our physical understanding of exoplanetary mass loss, by quantifying the influence of stellar outflows on atmospheric escape of close-in exoplanets. Escape plays a key role in planetary evolution, population, and potential to develop life. Stellar irradiation and outflows affect planetary mass loss: irradiation heats planetary atmospheres, which inflate and more likely escape; outflows cause pressure confinement around otherwise freely escaping atmospheres. This external pressure can increase, reduce or even suppress escape rates; its effects on exoplanetary mass loss remain largely unexplored due to the complexity of such interactions. I will fill this knowledge gap by developing a novel modelling framework of atmospheric escape that will, for the first time, consider the effects of realistic stellar outflows on exoplanetary mass loss. My expertise in stellar wind theory and 3D magnetohydrodynamic simulations is crucial for producing the next-generation models of planetary escape. My framework will consist of state-of-the-art, time-dependent, 3D simulations of stellar outflows (Method 1), which will be coupled to novel 3D simulations of atmospheric escape (Method 2). My models will account for the major underlying physical processes of mass loss. With this, I will determine the response of planetary mass loss to realistic stellar particle, magnetic and radiation environments and will characterise the physical conditions of the escaping material. I will compute how its extinction varies during transit and compare synthetic line profiles to atmospheric escape observations from, eg, Hubble and our NASA cubesat CUTE. Strong synergy with upcoming observations (JWST, TESS, SPIRou, CARMENES) also exists. Determining the lifetime of planetary atmospheres is essential to understanding populations of exoplanets. ASTROFLOW’s work will be the foundation for future research of how exoplanets evolve under mass-loss processes.

1 999 956 €

Start date: 2019-09-01, End date: 2024-08-31

Biomolecules exist in an aqueous environment of dipolar water molecules and solvated ions. Their structure and biological function are strongly influenced by electric interactions with the fluctuating water shell and ion atmosphere. Understanding such interactions at the molecular level is a major scientific challenge; presently, their strengths, spatial range and interplay with other non-covalent interactions are barely known. Going far beyond existing methods, this project introduces the new paradigm of a direct time-resolved mapping of molecular electric forces on sub-nanometer length scales and at the genuine terahertz (THz) fluctuation frequencies. Vibrational excitations of biomolecules at the interface to the water shell act as sensitive noninvasive probes of charge dynamics and local electric fields. The new method of time resolved vibrational Stark shift spectroscopy with THz external fields calibrates vibrational frequencies as a function of absolute field strength and separates instantaneous from retarded environment fields. Based on this knowledge, multidimensional vibrational spectroscopy gives quantitative insight in the biomolecular response to electric fields, discerning contributions from water and ions in a site-specific way. The experiments and theoretical analysis focus on single- and double-stranded RNA and DNA structures at different hydration levels and with ion atmospheres of controlled composition, structurally characterized by x-ray scattering. As a ground-breaking open problem, the role of magnesium and other ions in RNA structure definition and folding will be addressed by following RNA folding processes with vibrational probes up to milliseconds. The impact of site-bound versus outer ions will be dynamically separated to unravel mechanisms stabilizing secondary and tertiary RNA structures. Beyond RNA research, the present approach holds strong potential for fundamental insight in transmembrane ion channels and channel rhodopsins.

2 330 493 €

Start date: 2019-05-01, End date: 2024-04-30

Accurate determination of physical conditions of interstellar molecular clouds is a crucial step to better understand the life cycle of the interstellar matter and particularly the formation of stars and planets as well as the synthesis of organic molecules that may lead to emergence of life in the universe. A key parameter for the determination of these conditions from interstellar spectra is the calculation of accurate collisional rate coefficients of interstellar molecules with the most abundant species (H, He, H2 and e-). Whereas the knowledge of collisional processes has reached a certain level of maturity for collisions involving non-reactive molecules, very few reliable data exist for collisions involving reactive radicals and ions. The computation of such data is a real challenge since inelastic and reactive processes compete during collisions. In this project, we plan to overcome this complex problem and to provide collisional data for these radicals and ions in order to derive as much information as possible from the molecular spectra collected by current telescopes. As it is hardly possible to consider both collisional and reactive processes simultaneously, we will set up a new methodology based on quantum approach that allows obtaining accurate data. We will focus on molecular hydrides that are good candidates because of both their astrophysical importance and their quantum accessibility. We will carry out the determination of interaction potentials using quantum chemistry ab initio methods while the treatment of the dynamics of the nuclei will primarily be done using quantum time-independent reactive and non-reactive approaches. When exact quantum calculations will not be usable, innovative statistical quantum mechanical methods will also be explored. The new data will then be used in radiative transfer models and the predictions will be finally compared to observations in order to derive the abundances of reactive radicals with unprecedented accuracy.

1 802 625 €

Start date: 2019-07-01, End date: 2024-06-30

The CRISPR-Cas system has been extensively studied for its ability to cleave DNA. In contrast, studies of the ability of the system to acquire and integrate new DNA from invaders as a form of prokaryotic adaptive immunity, have lagged behind. This delay reflects the extreme enthusiasm surrounding the potential of using the system’s cleavage capabilities as a genome editing tool. However, the enormous potential of the adaptation process can and should arouse a similar degree of enthusiasm. My lab has pioneered studies on the CRISPR adaptation process by establishing new methodologies, and applying them to demonstrate the essential role of the proteins and DNA elements, as well as the molecular mechanisms, operating in this process. In this project, I will establish novel platforms for studying adaptation and develop them into biotechnological applications and research tools. These tools will allow me to identify the first natural and synthetic inhibitors of the adaptation process. This, in turn, will provide genetic tools to control adaptation, as well as advance the understanding of the arms race between bacteria and their invaders. I will also harness the adaptation process as a platform for diversifying genetic elements for phage display, and for extending phage recognition of a wide range of hosts. Lastly, I will provide the first evidence for an association between the CRISPR adaptation system and gene repression. This linkage will form the basis of a molecular scanner and recorder platform that I will develop and that can be used to identify crucial genetic elements in phage genomes as well as novel regulatory circuits in the bacterial genome. Together, my findings will represent a considerable leap in the understanding of CRISPR adaptation with respect to the process, potential applications, and the intriguing evolutionary significance.

2 000 000 €

Start date: 2019-12-01, End date: 2024-11-30