Essays about: "Stjärnorna"

Showing result 1 - 5 of 56 essays containing the word Stjärnorna.

  1. 1. Potassium in the Galactic Bulge - as traced by microlensed dwarf & sub-giant stars

    University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Author : Lukas Jönsson; [2023]
    Keywords : Nucleosynthesis; Galactic Bulge; Potassium; Non-Local-Thermal-Equilibrium; Physics and Astronomy;

    Abstract : During this report the potassium (K) trend in the Galactic Bulge, with respect to metallicity and various α-elements, has been computed and evaluated by a method of line synthesis on the 7698.96 ̊A KI line (7699 KI), where Non-Local-Thermal-Equilibrium (NLTE) effects have been considered. READ MORE

  3. 2. What limits the luminosity of red supergiants?

    University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Author : Eric Svensson; [2023]
    Keywords : Stellar evolution; Red supergiants; Red giants; Luminosity; Binary stars; Binary star systems; Binary star interactions; Binary stellar evolution; Humphreys-Davidson limit; Upper luminosity limit; BSE; Population synthesis; Simulations; M31; LMC; SMC; Metallicity; Mass transfer; Merging; Physics and Astronomy;

    Abstract : The observed upper limit of the luminosity of red supergiants, often called the Humphreys-Davidson limit, has recently been shown to be independent of metallicity and to not be explainable by single star evolution – findings that both contradict established ideas of the origins of the limit. It is now known that the vast majority of stars with sufficient mass to possibly evolve into red supergiants above the limit interact with companion stars at some point during their lives. READ MORE

  4. 3. Void Evolution and Cosmic Star Formation

    University essay from Uppsala universitet/Institutionen för fysik och astronomi

    Author : Joel Wasserman; [2023]
    Keywords : Void; Void Evolution; Cosmic Void; Star Formation Rate; Star Formation History; Cosmic Star Formation; Cosmology; Spherical Evolution Model; SvdW; Vdn; Excursion Set Theory; Excursion Set Formalism; Astrophysics; Astronomy; Cosmic Web; Matter Transfer; Tomrum; Tomrumsutveckling; Kosmiska Tomrum; Stjärnbildningshastighet; Stjärnbildningshistorik; Kosmisk stjärnbildning; Kosmologi; Sfärisk Evolutionsmodell; SvdW; Vdn; Exkursionsset teori; Exkursionsset Formalism; Astrofysik; Astronomi; Kosmiska Spindelnätet; Masstransport;

    Abstract : The rate at which stars have formed throughout the history of theuniverse is not constant, it started out slow, increased until around redshift ∼ 2 when it reversed and became slower again. The reason for this behaviour is still being investigated with various models and simulations usually based upon dark matter halos. READ MORE

  5. 4. Hyper-velocity stars from globular clusters hosting intermediate-mass black holes

    University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Author : Matilda Skantz; [2023]
    Keywords : Hypervelocity stars; run-away stars; stellar binary; intermediate mass black hole; globular cluster; Hills mechanism; Physics and Astronomy;

    Abstract : In 1988 Hills proposed that stars can gain velocities above 500 km s−1 if they are in a stellar binary which gets disrupted by a super massive black hole (SMBH). One of the stars would get trapped in an elliptical orbit around the SMBH while the other gets ejected and obtains a relatively high velocity. READ MORE

  6. 5. Combining Hipparcos and Gaia data: Improved Astrometric Calculations With Orvara

    University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Author : Melvin Tham; [2023]
    Keywords : Astrometry; Af Leporis; Smethells 119; Gliese 105; Gliese 86; Orvara; Hipparcos; Gaia; Physics and Astronomy;

    Abstract : Hipparcos and Gaia are two missions intended to catalogue positions and motions of stellar objects. Orvara is a computer program which aims to combine the data from these two missions to calculate Keplerian parameters for stellar systems. READ MORE