Sökning: "Stellar"

Visar resultat 1 - 5 av 172 uppsatser innehållade ordet Stellar.

  1. 1. The visibility of stellar transients in the Galactic Centre

    Kandidat-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/Astrofysik

    Författare :Jonathan Ström; [2024]
    Nyckelord :Physics and Astronomy;

    Sammanfattning : 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. LÄS MER

  3. 2. Measuring copper abundances in the Galactic Bulge

    Kandidat-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

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

    Sammanfattning : 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. LÄS MER

  4. 3. The quest for a classical bulge - a study of kinematics, abundances, and ages using microlensed dwarf stars and Gaia

    Master-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Författare :Calum Kvernes Macpherson; [2023]
    Nyckelord :Bulge; Milky Way; Kinematics; Galpy; Dwarf Stars; Physics and Astronomy;

    Sammanfattning : Context: We present an kinematical analysis of 90 F and G type dwarf, turn-off, and subgiant stars in the Galactic bulge. These stars were observed with high-resolution spectrographs during gravitational microlensing events This allowed for their ages, abundances, and radial velocities to be ascertained while they were significantly brighter. LÄS MER

  5. 4. Wavelength-dependent limb darkeningin the analysis oftransit spectroscopy of exoplanets

    L3-uppsats, Uppsala universitet/Institutionen för fysik och astronomi

    Författare :Alberto García Ribas; [2023]
    Nyckelord :;

    Sammanfattning : Limb darkening, an optical effect characteristic of stars, where the limb (edge) seemsto be darker than the centre of the stellar body; plays an important role in our under-standing of exoplanetary transits, as it is fundamental for developing light curve modelsthat can help to undercover extrasolar companions. To recover atmospheric featuresfrom exoplanets, a principal component analysis method is typically used. LÄS MER

  7. 5. Starshades: Geoengineering Solutions and Technosignatures in Direct Imaging Phase Curves

    Kandidat-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Författare :Claudia Skoglund; [2023]
    Nyckelord :Starshades; extraterrestrial intelligence; stellar evolution; technosignatures; phase curves; direct imaging; habitable zone.; Physics and Astronomy;

    Sammanfattning : The stellar luminosity increases as a star evolves which inevitably yields a higher temperature on planets in orbit around the star. It is reasonable to assume that intelligent civilizations would tackle this issue through installing artificial structures that can alter the radiation received by the planet. LÄS MER