The thesis addresses the long-term dynamical evolution of hierarchical multiple systems. First, we consider the evolution of orbits of stars orbiting a supermassive black hole (SBH). We... Show more The thesis addresses the long-term dynamical evolution of hierarchical multiple systems. First, we consider the evolution of orbits of stars orbiting a supermassive black hole (SBH). We study the long-term evolution and compute tidal disruption rates of stars by the SBH. Such disruption events reveal the physics and properties of stars and SBHs. Furthermore, we study the dynamics of planetesimals in the galactic center (GC). When planetesimals are tidally disrupted by the SBH, this can produce a potentially observable flare. We compute the rates of such disruptions, and find rates consistent with observations, suggesting that planetesimals are formed in the GC around stars, similarly to stars in the solar neighbourhood. Subsequently, we consider the long-term evolution of hierarchical quadruple systems. We appy our techniques to provide an explanation for the lack of transiting circumbinary planets around short-period binaries. Lastly, we generalise our methods, and apply them to study the implications of the long-term dynamical evolution of multiplanet systems on hot Jupiters (HJs). We find that the long-term dynamical evolution in multiplanet systems can explain at most a few per cent of the observed HJs, unless the efficiency of tidal dissipation is much higher than is currently believed. Show less
This thesis focus on the interaction between M dwarf stellar winds and Galactic cosmic rays and the possible effects on the habitability of exoplanets. We use numerical simulations to describe the... Show moreThis thesis focus on the interaction between M dwarf stellar winds and Galactic cosmic rays and the possible effects on the habitability of exoplanets. We use numerical simulations to describe the stellar winds of M dwarfs using observable constraints, such as the mass-loss rate, X-ray luminosity, and magnetic field strength/flux. Additionally, we use numerical simulations to describe the propagation of Galactic cosmic rays within M dwarf planetary systems. With these simulations, we can calculate the flux of Galactic cosmic rays reaching exoplanet magnetospheres/atmospheres. Measuring cosmic ray fluxes in exoplanet atmospheres is yet not possible, but cosmic rays are an important ingredient in the context of planetary habitability. For this reason, quantifying these fluxes is essential to complete the habitability “puzzle”. Future exoplanet atmosphere observations with space telescopes, such as the JWST and the ARIEL, will enable us to constrain cosmic ray fluxes in exoplanet atmospheres. Show less