Sökning: "Binary Stars"

Visar resultat 1 - 5 av 33 uppsatser innehållade orden Binary Stars.

1. 1. What limits the luminosity of red supergiants?

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

   Författare :Eric Svensson; [2023]
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

3. 2. Intermediate-mass black hole binary as an origin of super-massive black holes

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

   Författare :Isabelle Signe Maj Maria Thord; [2023]
   Nyckelord :Intermediate-mass black holes; binary; merger; hardening; encounters; Physics and Astronomy;

   Sammanfattning : Galactic nuclei contain super-massive black holes (SMBHs), nuclear stellar clusters (NSCs), or both. In the NSC, intermediate-mass black holes (IMBHs) are likely to reside and form highly eccentric binaries. Over time, the orbit of a binary could harden via interaction with surrounding low-mass stars. LÄS MER

4. 3. Origin of blue straggler stars in the Milky Way halo

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

   Författare :Adam Brcek; [2023]
   Nyckelord :Blue Straggler; Galactic Halo; Spectroscopic Surveys; Binary Star Evolution; Mass Transfer; Physics and Astronomy;

   Sammanfattning : Blue straggler stars (BSSs) are exotic stellar objects that appear to be younger than the age of the population they come from suggests. They are observed as the extension of the main sequence stars, beyond the turn-off point. LÄS MER

5. 4. Atomic Structure Calculations Using Configuration-Interaction And Many-Body Perturbation Theory For Spectral Modelling Of Neutron Star Mergers : Example Of Ce I - Iv

   L3-uppsats, Uppsala universitet/Teoretisk fysik

   Författare :Fredrik Plane; [2023]
   Nyckelord :Computational atomic physics; Atomic physics; Physics; Astronomy; Astrophysics; Neutron stars; Stars; Relativisitc atomic physics; Configuration-interaction; Perturbation theory; Many-body perturbation theory;

   Sammanfattning : The binary neutron star merger of 2017 and its corresponding electromagnetic signature resembling that of a kilonova has been one of the most groundbreaking astrophysical occurrences in the last decade. Indications of r-process nucleosynthesis in this event presents new opportunities for learning about the astrophysical origin of heavy elements. LÄS MER

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

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

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

   Sammanfattning : 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. LÄS MER