Essays about: "Astrofysik"

Showing result 1 - 5 of 97 essays containing the word Astrofysik.

  1. 1. Gravitational Collapse of a Massless Scalar Field in a Theory of Minimally Modified Gravity

    University essay from KTH/Fysik

    Author : Atabak Fathe Jalali; [2024]
    Keywords : Theoretical physics; astrophysics; modified gravity; minimally modified gravity; gravitational collapse; VCDM; scalar collapse; apparent horizon; numerical relativity; Teoretisk fysik; astrofysik; modifierad gravitation; minimalt modifierad gravitation; gravitationskollaps; VCDM; skalär kollaps; uppenbar horisont; numerisk relativitet;

    Abstract : This thesis explores the spherically symmetric gravitational collapse of a massless scalar field in a minimally modified gravity theory denoted VCDM (V replaces $\Lambda$ in the $\Lambda$CDM abbreviation), a class of theories propagating the same degrees of freedom as general relativity at the expense of broken 4D diffeomorphism invariance. Numerical evolution of the equations of motion reveals that for small initial scalar profile amplitudes, no black hole forms from the collapse. READ MORE

  3. 2. The visibility of stellar transients in the Galactic Centre

    University essay from Lunds universitet/Fysiska institutionen; Lunds universitet/Astrofysik

    Author : Jonathan Ström; [2024]
    Keywords : Physics and Astronomy;

    Abstract : A semi-analytical simulation was developed to evaluate the K-band magnitudes of Red Giants [0.96 - 1.02 M⊙] orbiting the supermassive black hole in the galactic centre. The model assumed star formation between 10-12 Gyrs ago and by following the IMF and applying a random age condition, a stellar population was created. READ MORE

  4. 3. Exocomets in the β Pictoris system

    University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Author : Klaudia Jaworska; [2024]
    Keywords : Physics and Astronomy;

    Abstract : Comets have been a source of fascination throughout the history of man. In recent years, advances in technology have opened up for the study of extrasolar objects, among them exocomets. The first exocomets were observed in the β Pictoris system almost 50 years ago and the system has been of interest ever since. READ MORE

  5. 4. Measuring copper abundances in the Galactic Bulge

    University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Author : Nikolei Höglinger; [2024]
    Keywords : Copper; Galaxy: abundances; Galaxy: bulge; Chemical Evolution; Physics and Astronomy;

    Abstract : Context: The chemical evolution of Cu in the Galactic bulge have been studied in a few studies using red giant branch stars, but the ages of individual red giant stars are difficult to determine. In addition, the bulge has been a challenging region of the Milky Way galaxy to obtain high-resolution spectra of stars, except when observing through certain few small fields into the bulge that are known to have low extinction. READ MORE

  6. 5. N-body simulations of exoplanets and their moons

    University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Author : Lydia Schollmeier; [2024]
    Keywords : Physics and Astronomy;

    Abstract : The planet-planet interactions in a many-planet system cannot be analytically calculated. Instead, they have to be investigated by using an N-body simulation. I discuss three questions about the N-body interactions in planetary systems: The first two are on the system 55 Cnc, a system with five known planets around a K-type star. READ MORE