Sökning: "accretion"

Visar resultat 1 - 5 av 62 avhandlingar innehållade ordet accretion.

  1. 1. Turbulence-Assisted Planetary Growth : Hydrodynamical Simulations of Accretion Disks and Planet Formation

    Författare :Wladimir Lyra; Nikolai Piskunov; Thomas Henning; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; accretion; accretion disks; hydrodynamics; instabilities; methods: numerical; solar system: formation; planets and satellites: formation; magnetohydrodynamics MHD ; turbulence; diffusion; stars: planetary systems: formation; Astronomy and astrophysics; Astronomi och astrofysik;

    Sammanfattning : The current paradigm in planet formation theory is developed around a hierarquical growth of solid bodies, from interstellar dust grains to rocky planetary cores. A particularly difficult phase in the process is the growth from meter-size boulders to planetary embryos of the size of our Moon or Mars. LÄS MER

  2. 2. An Observational Study of Accretion Processes in T Tauri Stars

    Författare :Henricus Cornelis Stempels; Nikolai Piskunov; Gibor Basri; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Star formation; T Tauri stars; Emission lines; Accretion; NLTE radiative transfer; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; Astronomi;

    Sammanfattning : This thesis is a detailed observational study of the accretion processes in T Tauri stars (TTS). The interaction between the central star, the circumstellar disk and the magnetic field gives rise to a wide range of features in the spectra of TTS. LÄS MER

  3. 3. X-ray variability in Galactic high-mass black hole binaries

    Författare :Magnus Axelsson; Stefan Larsson; Chris Done; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Accretion; high-energy astrophysics; temporal variability; X-ray binaries; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; astronomi;

    Sammanfattning : The stars of the night sky can to the naked eye appear to be steady and unchanging, apart from the twinkling created by air moving in the atmosphere. However, when viewed in X-rays, the sky is far from constant, with detectable changes occurring on very short timescales.Black hole X-ray binaries are strong sources of X-rays. LÄS MER

  4. 4. Magnetohydrodynamics of Turbulent Accretion Disks and Planet Formation

    Författare :Wladimir Lyra; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Astronomy and astrophysics; Astronomi och astrofysik;

    Sammanfattning : Planets have long been believed to form in disks of gas and dust around youngstars, interacting with their surroundings via a setof complex and highly nonlinear processes. In the core accretion scenario forgiant planet formation dust coagulates first into km-sized icyand rocky planetesimals that further collide, formingprogressively larger solid bodies that eventually give rise to cores of severalEarth masses. LÄS MER

  5. 5. Ice accretion and ice adhesion to polymer material

    Författare :Lars-Olof Andersson; Luleå tekniska universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vattenteknik; Water Resources Engineering;

    Sammanfattning : .... LÄS MER