Sökning: "accretion"

Visar resultat 1 - 5 av 39 uppsatser innehållade ordet accretion.

  1. 1. How did Jupiter form?

    Kandidat-uppsats, Lunds universitet/Astronomi

    Författare :Calle Ahlgren; [2019]
    Nyckelord :Planet formation; Planet migration; Physics and Astronomy;

    Sammanfattning : Two relatively new concepts in planetary science are planetary migration; wherein the planets migrate through the protoplanetary disk as they form, and pebble accretion; wherein the planetesimals which become terrestrial planets and giant planet cores grow through the accretion of small pebbles. Planetary migration has become a generally accepted concept but there is still much to be learned even about how it affected the formation of our own solar system. LÄS MER

  2. 2. Tuned sustainable anodic coatings for reduced ice adhesion

    Master-uppsats, Linköpings universitet/Molekylär ytfysik och nanovetenskap

    Författare :Thirza Poot; [2019]
    Nyckelord :aluminum alloys; tartaric-sulfuric acid anodizing; ice adhesion; silanization; hydrothermal sealing; contact angle; SEM; corrosion;

    Sammanfattning : Aluminum alloys are widely used materials in the aircraft industry due to their high specific strength and durability. The natural corrosion resistance of aluminum can be improved through an electrochemical anodizing process. LÄS MER

  3. 3. The fate of pebbles and planetesimals entering protoplanetary envelopes

    Master-uppsats, Lunds universitet/Astronomi

    Författare :Emil Zadera; [2019]
    Nyckelord :Planet formation; planet; protoplanet; protoplanetary envelope; protoplanetary atmosphere; protoplanetary growth; planetary growth model; accretion rate; vapour blob; vapourblob; vapour planet; transport of water; water on planet; pebbles; planetesimals; pebble accretion; planetesimal accretion; meteors; ablation; fragmentation; sublimation; protoplanetary disk; MMSN; accretion window; accretion channel; accretion; destruction; disruption; terminal velocity; gas; gasflow; shearingbox; exoplanet; Physics and Astronomy;

    Sammanfattning : Planetary embryos grow by the accretion of solid dust-material, ranging from cm- to m-sized pebbles up to km-sized planetesimals. However, the underlying size-distribution of the accreted material is poorly understood. LÄS MER

  4. 4. Examining variable galactic nuclei with the help of astronomical databases and archives

    Kandidat-uppsats, Uppsala universitet/Teoretisk astrofysik

    Författare :Jimmy Kjellqvist; [2019]
    Nyckelord :Active Galactic Nuclei; Variable stars; Variable objects; Aktiva Galaxkärnor; Variabla stjärnor; Variabla objekt;

    Sammanfattning : There exists many astronomical objects that vary in brightness. Objects such as variable stars like the Cepheids that periodically expands and contracts their outer layers, or the active galactic nuclei (AGN) where accretion of matter into a black hole generates a often varying brightness. LÄS MER

  5. 5. Formation and Evolution of Protoplanetary Disks

    Master-uppsats, Lunds universitet/Astronomi

    Författare :Johan Appelgren; [2019]
    Nyckelord :protoplanetary disk; protoplanetary disk formation; protoplanetary disk evolution; planet formation; Physics and Astronomy;

    Sammanfattning : A star forms with a surrounding protoplanetary disk after the collapse of a molecular cloud core. Subsequently, over a period of several Myr this protoplanetary disk of dust and gas is accreted onto the host star. We model the formation and evolution of such a protoplanetary disk using a one-dimensional numerical model. LÄS MER