Sökning: "stellar parameters"

Visar resultat 21 - 25 av 58 uppsatser innehållade orden stellar parameters.

  1. 21. Have Radial Velocity Surveys Missed Any Planets?

    Kandidat-uppsats, Lunds universitet/Astronomi - Genomgår omorganisation; Lunds universitet/Fysiska institutionen

    Författare :Shah Raj; [2021]
    Nyckelord :radial velocity survey; transit method; exoplanet; habitable zone; habitable zone boundaries; HZ; early Mars; recent Venus; stability; instability; chaos; REBOUND; MEGNO; MEGNO maps; Hill sphere; stable systems; unstable systems; Physics and Astronomy;

    Sammanfattning : The project was aimed at numerically assessing exoplanetary systems to distinguish their capabilities of hosting additional planets. The shortcomings of the radial velocity method sometimes causes hindrance in the detection of terrestrial planets. LÄS MER

  3. 22. Towards a high resolution view of infrared line formation

    Master-uppsats, Lunds universitet/Astronomi - Genomgår omorganisation

    Författare :Martin Schmidt Montelius; [2021]
    Nyckelord :Spectroscopy; Near infrared; K giants; Galactic archeaology; Galactic chemical evolution; Abundances; Milky Way; Physics and Astronomy;

    Sammanfattning : Observing in the infrared has many benefits, such as seeing through the interstellar dust in the galaxy, easier use of adaptive optics, and better flux ratios for direct observations of exoplanets. Before the infrared spectral range can be utilised for highly accurate stellar spectroscopy there is a need for a better understanding of both stellar modelling and the atomic physics that go into forming spectral lines. LÄS MER

  4. 23. Modelling stellar streams around the Milky Way

    Master-uppsats, Lunds universitet/Astronomi - Genomgår omorganisation

    Författare :Hyerin Jang; [2021]
    Nyckelord :Physics and Astronomy;

    Sammanfattning : Stellar streams around the Milky Way (MW) have been observed by wide sky surveys, and studied to understand the mass distribution of the MW. This is because streams are formed by a disruption of a globular cluster or a dwarf galaxy under the influence of the gravitational field of the MW. LÄS MER

  5. 24. Isochrone and chemical ages of stars in the old open cluster M67

    Master-uppsats, Uppsala universitet/Observationell astrofysik

    Författare :Julia Ahlvind; [2021]
    Nyckelord :solar twin; Messier 67; M67; open cluster; isochrone; chemical clock;

    Sammanfattning : The open cluster Messier 67 is known to have chemical composition, metallicity and age (~ 4 Gyr) close to the Sun. Therefore, it is advantageous for stellar physical studies and of stellar evolution, in particular for solar like stars within the cluster. LÄS MER

  7. 25. Advanced Characterization of Exoplanet Host Stars

    Master-uppsats, Uppsala universitet/Observationell astrofysik

    Författare :Khaled Al Moulla; [2020]
    Nyckelord :stars: exoplanet hosts - fundamental parameters - spectroscopy: HARPS - SME; stjärnor: exoplanetvärdar - fundamentala parametrar - spektroskopi: HARPS - SME;

    Sammanfattning : The spectroscopic determination of stellar properties is important for subsequent studies of exoplanet atmospheres. In this thesis, HARPS data for 6 exoplanet-hosting, late-type stars is processed to achieve an average signal-to-noise ratio of ~105. LÄS MER