Filtyp
Gravitational light deflection in the Solar System can be detected by high precision astrometric measurements. We discuss the parametrized post-Newtonian framework and the comparison of metric theories of gravity. At the precision of a few micro-arcseconds, Gaia data will permit tests of the PPN parameters beta and gamma and to distinguish monopole and quadrupole gravitational light deflection. Ac
The observations of circumbinary planets have confirmed that these can in fact be stable. While previous studies on circumbinary planets have been done, not many have been made on systems containing multiple circumbinary planets on eccentric orbits. In this thesis, the effects a binary star system of solar mass would have on the Solar System is investigated. Using the program MERCURY, numerous int
In this thesis, I investigate if the binaries that are being tidally disrupted by means of the Hills mechanism, producing hypervelocity stars, could have been transported to the galactic centre by two-body scattering. To survive a scattering event, the binary must be hard, meaning that the binding energy of the binary is higher than the kinetic energy of the collider. If the binary is soft, the bi
Double neutron star binaries (DNSBs) in the mHz gravitational wave (GW) regime are an important group of objects which the GW detector LISA will be able to observe. The detection and parametrization of these objects will help develop our current understanding of neutron star formation and evolution. In this thesis, we synthesize a group of DNSBs using data from Church et al. (2011) and normalize t
The aim of this thesis is to get a better understanding of the evolution of the Milky Way stellar disc by looking at the abundance ratios for neutron-capture elements in thin and thick disc stars. In this project the formation of our Galaxy’s thin and thick disc was studied by analysing 10 different neutron-capture elements in field stars measured by Gaia-ESO. The methodology to determine if this
The first part of this thesis deals with the dynamical estimation of the Oort constants using proper motions and parallaxes provided from the Gaia-DR1 TGAS catalogue. The photometric information was provided by the 2MASS catalogue. The Oort constants calculated from the TGAS catalogue are compared to those obtained from the original Hipparcos catalogue in order to attempt to estimate how well Gaia
The orbital approximation for stellar streams is the assumption that all stars in a stream can be described as following the same orbit. In this thesis, I evaluate this approximation as a method for constraining the potential of the Milky Way. I wrote a program in MATLAB which integrates the orbits of test particles in a potential model which resembles that of the Milky Way's halo and disc. Th
One of the biggest mysteries astronomers wish to unveil is the formation and evolution of galaxies. Properties of our own galaxy, the Milky Way, can provide great insight into these. The star formation rate (SFR) and whether it varies with distance from the galactic centre (GC), is one of these properties. Studies indicate that the SFR is higher in the bulge region than in the local thick disk of
The observed high orbital eccentricities of many giant exoplanets is thought to be the result of gravitational scattering between planets. Outcomes of planet-planet scattering can result in some planets being lost by ejections into interstellar space, or collisions between planets or with the star. The likelihood of collisions for a planet with a certain mass, increases with larger radii. After p
The motivation for the project is to investigate what happens if I add a second Earth in the Solar System and project it forward in time. I add an Earth mass planet (called Earth two) in the same orbit as the Earth on the other side of the Sun (i.e. six months ahead of the original Earth). I then investigate how the perturbation of the second Earth effects the Solar System in the short and the lon
In this work we study the spectra of 423 stars in the Milky Way disk in order to determine their zinc abundances. The methodology to determine elemental abundances consists of synthesising sets of spectra with varying zinc abundances and comparing them with the observed spectra to find the best fit. The aim of the project was to compare the spectra syn- thesis method used here to Bensby et al. (2014
Data from NASA's Kepler space telescope, which searches for exoplanets via the transit method, produced 1108 new planetary candidates in 2013 with a total of 91% being smaller than Neptune in size. These were mostly super-Earths, terrestial planets between Earth and Neptune in size, with orbits around 10 days. In order for any theory of planet formation to be valid it must be able to account
Studies of the Milky Way including how it formed and evolved through time are the key to understanding how other galaxies behave. The Milky Way is the most convenient galaxy to study, because the close proximity of stars means astronomers can collect precise spectral and dynamical data from individual stars. By combining the chemical and dynamical aspects, it is possible to pinpoint stars which ha
The all-sky survey of Gaia will generate vast amounts of astrometric data, in which there are expected to be thousands of planets found. Finding a system of $n_\textup{p}$ planets requires fitting of a total $5+7n_\textup{p}$ parameters: five astrometric and seven Keplerian parameters for every planet. The problem is thus highly non-linear and computationally prohibitive. After exploiting the line
The properties of the early Milky Way are quite mysterious and some are completely unknown even today. This study is the first one ever to analyze the mass distribution of Population III bulge stars. Using the fitting code STARFIT, we perform an analysis of 65 bulge metal-poor stars obtained by the EMBLA survey to estimate the IMF (initial mass function) of the very first stars that defined our ga
To understand the evolution of our galaxy, the chemical abundance patterns and trends within the stars of the different regions are explored. The process of synthesizing these elements reveals key details about the way the stars and, therefore, the galaxy formed. This project focused on the element potassium, K, and specifically its absorption line 7699 Å. The local thermodynamic equilibrium (LTE)
