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Spectral Analysis of Neutron Capture Elements in the Laboratory and Stars

Lundqvist, Martin LU (2006)
Abstract (Swedish)
Popular Abstract in Swedish

Grundämnena tyngre än järns ursprung är en vital fråga inom historien on och evolutionen av vår galax. Grundämnena upp till och med järngruppen produceras huvudsakligen genom fusion inne i stjärnor som ger dem deras energi. De ännu tyngre grundämnena produceras istället huvudsakligen genom neutroninfångningsprocesser: Den svaga s-processen, huvud-s-processen och r-processen.Den svaga s-processen ansvarar för en en del av ämnena upp till ungefär A=100 och tros vara active under helium förbränning i kärnan av stjärnonr mer än 10 gånger mer massiva än solen. Huvud-s-processen är aktive i AGB-stjärnor och r-processen är aktiv i supernovor.



Den här avhandlingen studerar olika... (More)
Popular Abstract in Swedish

Grundämnena tyngre än järns ursprung är en vital fråga inom historien on och evolutionen av vår galax. Grundämnena upp till och med järngruppen produceras huvudsakligen genom fusion inne i stjärnor som ger dem deras energi. De ännu tyngre grundämnena produceras istället huvudsakligen genom neutroninfångningsprocesser: Den svaga s-processen, huvud-s-processen och r-processen.Den svaga s-processen ansvarar för en en del av ämnena upp till ungefär A=100 och tros vara active under helium förbränning i kärnan av stjärnonr mer än 10 gånger mer massiva än solen. Huvud-s-processen är aktive i AGB-stjärnor och r-processen är aktiv i supernovor.



Den här avhandlingen studerar olika aspekter av neutroninfångnings-nucleosyntes. Förbättrade oscillator styrkor för Hf II, Os I och Ir I har bestämts och applicerade i spektralanalys av den metallfattiga stjärnan CS31082-001 och de nya halterna förbättrar överensstämmelsen med den rena r-process-trend man ser bland grundämneshalterna i denna stjärna. Isotopskift i Sm II linjer can användas för att direkt mäta andelen r- och s- process ämnen i ett objekt. Denna metod har applicerats på CS31082-001 och den föreslår att stjärnan innenhåller framför allt r-process ämnen. En sökning efter bevis på svaga s-process ämnen i alpha Orionis är också genomförd och resultat visar en mycket hög halt av strontium. (Less)
Abstract
The pedigree of the elements heavier than iron is a vital question in the history and evolution of our galaxy. The elements up to and including those of the iron group are produced mainly through fusion processes within stars, giving the stars their energy. The even heavier elements are instead mainly produced through neutron capture processes: weak s-process, main s-process and r-process. The weak s-process is responsible for a portion of the nucleons up to about A=100 and is thought to be active mainly during helium-core burning in stars more massive than ~10 Msol. The main s-process and the r-process produce all heavier elements. The main s-process is active in AGB stars and the r-process is active in supernovae.



This... (More)
The pedigree of the elements heavier than iron is a vital question in the history and evolution of our galaxy. The elements up to and including those of the iron group are produced mainly through fusion processes within stars, giving the stars their energy. The even heavier elements are instead mainly produced through neutron capture processes: weak s-process, main s-process and r-process. The weak s-process is responsible for a portion of the nucleons up to about A=100 and is thought to be active mainly during helium-core burning in stars more massive than ~10 Msol. The main s-process and the r-process produce all heavier elements. The main s-process is active in AGB stars and the r-process is active in supernovae.



This thesis deals with different aspects of neutron capture nucleosynthesis. Improved oscillator strengths and wavelengths for Hf II, Os I and Ir I have been determined and applied to the spectrum analysis of the metal-poor halo star CS31082-001, and the new abundances improve the abundance trend showing a pure r-process content of this star. Isotope shift in Sm II lines can be used to allow us to directly measure the r- vs s- process content in an object. This method is applied to CS31082-001, and it suggests that the star contains predominantly r-processed material. A search for evidence of weak s-process elements in alpha Orionis is also conducted and results show a strong enhancement of strontium. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Nissen, Poul Erik, Dept. Physics and Astronomy, University of Aarhus, Denmark
organization
publishing date
type
Thesis
publication status
published
subject
keywords
cosmic chemistry, Astronomy, space research, Atom- och molekylärfysik, Atomic and molecular physics, Astronomi, Sm, Hf, Os, Ir, Neutron capture processes, rymdvetenskap, kosmisk kemi, cool stars, Spectroscopy, atomic data
pages
134 pages
publisher
Lund Observatory, Lund University
defense location
Lundmarksalen Lund Observatory Sölvegatan 27 Lund
defense date
2006-09-30 10:15
ISBN
978-91-628-6920-5
language
English
LU publication?
yes
id
3336790a-9c06-4645-a72c-477e8bc07fa9 (old id 547168)
date added to LUP
2007-09-05 10:38:09
date last changed
2016-09-19 08:45:12
@misc{3336790a-9c06-4645-a72c-477e8bc07fa9,
  abstract     = {The pedigree of the elements heavier than iron is a vital question in the history and evolution of our galaxy. The elements up to and including those of the iron group are produced mainly through fusion processes within stars, giving the stars their energy. The even heavier elements are instead mainly produced through neutron capture processes: weak s-process, main s-process and r-process. The weak s-process is responsible for a portion of the nucleons up to about A=100 and is thought to be active mainly during helium-core burning in stars more massive than ~10 Msol. The main s-process and the r-process produce all heavier elements. The main s-process is active in AGB stars and the r-process is active in supernovae.<br/><br>
<br/><br>
This thesis deals with different aspects of neutron capture nucleosynthesis. Improved oscillator strengths and wavelengths for Hf II, Os I and Ir I have been determined and applied to the spectrum analysis of the metal-poor halo star CS31082-001, and the new abundances improve the abundance trend showing a pure r-process content of this star. Isotope shift in Sm II lines can be used to allow us to directly measure the r- vs s- process content in an object. This method is applied to CS31082-001, and it suggests that the star contains predominantly r-processed material. A search for evidence of weak s-process elements in alpha Orionis is also conducted and results show a strong enhancement of strontium.},
  author       = {Lundqvist, Martin},
  isbn         = {978-91-628-6920-5},
  keyword      = {cosmic chemistry,Astronomy,space research,Atom- och molekylärfysik,Atomic and molecular physics,Astronomi,Sm,Hf,Os,Ir,Neutron capture processes,rymdvetenskap,kosmisk kemi,cool stars,Spectroscopy,atomic data},
  language     = {eng},
  pages        = {134},
  publisher    = {ARRAY(0x9c539c8)},
  title        = {Spectral Analysis of Neutron Capture Elements in the Laboratory and Stars},
  year         = {2006},
}