Sökning: "nebulae"

Visar resultat 1 - 5 av 7 avhandlingar innehållade ordet nebulae.

  1. 1. Measurements of High-Precision Atomic Data with Applications to Astrophysics and Cosmology

    Författare :Maria Aldenius; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atomic data; Ca; Cr; Fe; Mn; Mg; metal-poor stars; fine-structure constant; Fourier transform spectroscopy; nebulae; oscillator strengths; spectroscopy; wavelengths; Ti; Zn; Astronomy; Astronomi; Atomic and molecular physics; Atom- och molekylärfysik; rymdvetenskap; space research; cosmic chemistry; kosmisk kemi; branching fractions;

    Sammanfattning : Investigations of astrophysical spectra require accurate atomic data, such as wavelengths and transition probabilities. This thesis provides high-precision atomic data for astrophysical and cosmological applications. The measurements have been carried out using Fourier transform spectrometry on light produced in a hollow cathode light source. LÄS MER

  3. 2. Supernova remnants and their pulsar wind nebulae

    Författare :Natalia Lundqvist; Göran Olofsson; Robert Fesen; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pulsars; supernovae; ISM; Astronomy; astronomi;

    Sammanfattning : Massive stars die in powerful stellar explosions, so-called supernovae. In most cases, a neutron star or a black hole is expected to form in the center. The ejected material in these explosions expands out into the surroundings for tens of thousands of years, forming a supernova remnant. If a rapidly rotating neutron star, i. LÄS MER

  4. 3. Reaching for the Stars : Studies in the History of Swedish Stellar and Nebular Astronomy, 1860–1940

    Författare :Gustav Holmberg; Research Policy Institute (RPI); []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; HUMANIORA; HUMANITIES; stellar astronomy; history of astronomy; astrophysics; history of modern Swedish science; scientific practice; Astronomy; Astronomi;

    Sammanfattning : This study considers astrophysics, stellar and nebular astronomy in Sweden. Emphasis is on the role of scientific technologies and practice, and the emergence of a modern observational astronomy, supplanting classical astronomy as the most vital field of Swedish astronomy. LÄS MER

  5. 4. The faintest stars : A study of white, red and brown dwarfs

    Författare :Leif Festin; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; brown dwarfs; white dwarfs; M dwarf; low luminosity; luminosity function; mass function; Pleiades; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; astronomi; Astronomy;

    Sammanfattning : The local space density of the faintest stars, including M dwarfs, white dwarfs and brown dwarfs has been studied by two different methods.By using dark nebulae as opaque outer screens, the luminosity functions of M dwarfs and white dwarfs were studied as volume-limited and dynamically unbiassed foreground samples. LÄS MER

  7. 5. Companion wind shaping in binaries involving an AGB star

    Författare :Lam Doan; Sofia Ramstedt; Eric Lagadec; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB and post-AGB stars; mass-loss; radio lines; binaries; wind shaping; Astronomy; Astronomi;

    Sammanfattning : Stars of initial masses between 0.8-8 M☉ will become "asymptotic giant branch" (AGB) stars during the final stages of their evolution. During this phase, the stars are characterized by low velocity and high-density winds. LÄS MER