Sökning: "Stellar atmosphere"

Visar resultat 1 - 5 av 24 uppsatser innehållade orden Stellar atmosphere.

  1. 1. 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

  3. 2. The chemical evolution of the Milky Way: pushing APOGEE to higher precision and accuracy

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

    Författare :Erik Fridén; [2023]
    Nyckelord :Physics and Astronomy;

    Sammanfattning : In the recent decade, a rapid increase in all-sky spectroscopic surveys has occurred, and with it, the wealth of observational data and information on our Galaxy. Consequently, numerous detections of new structures, such as new open clusters, accreted and in-situ components, are discovered. LÄS MER

  4. 3. Laboratory starlight simulator for future space-based heterodyne interferometry

    Master-uppsats, Luleå tekniska universitet/Rymdteknik

    Författare :William Karlsson; [2023]
    Nyckelord :Angular resolution; Astronomy; Coherence length; Digital delay lines; Fiber optical circuit; Heterodyne interferometry; Interference; Laboratory starlight simulator; NIR light Near-Infrared ; Optical path differences; Space exploration; Starlight; Testbed environment;

    Sammanfattning : In astronomy, interferometry by ground-based telescopes offers the greatest angular resolution. However, the Earth´s atmosphere distorts the incident wavefront from a celestial object, leading to blurring and signal loss. It also restricts the transmission of specific wavelengths within the electromagnetic spectrum. LÄS MER

  5. 4. Estimating stellar limb darkening using exoplanet transits

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

    Författare :Sora Ishida; [2023]
    Nyckelord :Limb-darkening; CHEOPS; Transit; Exoplanet; PYCHEOPS; Physics and Astronomy;

    Sammanfattning : The brightness of the stars is not uniform over the surface as it varies depending on the wavelength and the atmosphere that the light propagates. Limb darkening is an optical effect caused by a decrease in brightness of the star towards the edge. LÄS MER

  7. 5. Simulations of the Tenuous Upper Atmospheres of Exoplanets

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

    Författare :Lucian Spitzner; [2023]
    Nyckelord :astronomy; astrophyics; exoplanets; transmission spectroscopy; magnetic fields; atmospheres; ions; Physics and Astronomy;

    Sammanfattning : Over the last decade, the interest in research on extraterrestrial planets has expanded dramatically. With the number of confirmed exoplanets having increased tenfold over the last ten years, we now know that many different types of exoplanets exist. LÄS MER