Sökning: "chemically peculiar"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden chemically peculiar.

  1. 1. Advances in Stellar Astrophysics from Laboratory Spectroscopy

    Författare :Stefan Ivarsson; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; iridium; osmium; uranium; oscillator strengths; Spectroscopy; term analysis; line profiles; line structure; astrophysics; Sun; Chi Lupi; 17 Comae A; chemically peculiar; praseodymium; stars; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:2004:Ivarsson;

    Sammanfattning : Investigation of astrophysical plasmas, such as stellar atmospheres, require both knowledge of atomic structure and data. We present laboratory instruments, techniques and tools for acquisition of the data required to derive important atomic parameters such as, wavelengths, oscillator strengths and line profiles. LÄS MER

  3. 2. Laboratory and Stellar Spectra in High Resolution: Studies of Fe, Pt and Tl in Peculiar Stars

    Författare :Gabriele Kalus; Fysiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; high-resolution spectroscopy; hyperfine structure; peculiar stars; iron; platinum; lead; upsilon Sagittarii; HR7775; chi Lupi; isotope shift; Atomic and molecular physics; Atom- och molekylärfysik; Fysicumarkivet A:1997:Kalus;

    Sammanfattning : The near-infrared spectrum of upsilon Sagittarii has been registered using the SOFIN high resolution spectrometer on the Nordic Optic Telescope, La Palma. For the first time 4f-5g transitions of Fe II in any astrophysical spectrum have been identified. LÄS MER

  4. 3. Investigations of Heavy Elements in Am and HgMn stars

    Författare :Linus Dolk; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; HgMn stars; spectroscopy; heavy elements; Astronomi; Astronomy; Chemically peculiar stars; Am star; Fysicumarkivet A:2002:Dolk;

    Sammanfattning : The relationship between the HgMn and Am classes of chemically peculiar stars has been investigated primarily by observing abundances of heavy elements, including Pr, Nd, Hg, Tl and Bi. The main objective of the investigation has been to gather observational evidence to provide a better understanding of the mechanisms producing the abundance anomalies of these stars, and to establish the relationship between the two classes. LÄS MER

  5. 4. Magnetic fields and chemical maps of Ap stars from four Stokes parameter observations

    Författare :Naum Rusomarov; Oleg Kochukhov; Nikolai Piskunov; Werner Weiss; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chemically peculiar stars; magnetic fields; spectropolarimetry; Doppler imaging; stellar atmospheres; Astronomy with specialization in Astrophysics; Astronomi med intiktning mot astrofysik; Astronomy; Astronomi;

    Sammanfattning : Our knowledge of stellar magnetic fields relies almost entirely on circular polarization observations, which has historically limited our understanding of the stellar magnetic field topologies. Recently, it has become possible to obtain phase-resolved high-resolution spectropolarimetric observations in all four Stokes parameters for early-type magnetic stars. LÄS MER

  7. 5. The Milky Way as seen through Neutron-Capture Elements

    Författare :Rebecca Forsberg; Astrofysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemical abundances; Galactic archaeology; chemically peculiar star; heavy elements; Galactic disk; Galactic bulge; Galactic chemical evolution;

    Sammanfattning : Through stars, the formation and evolution of the Galaxy goes hand-in-hand with the cosmic origin of the elements. As stars form, they carry chemical fingerprints of their birthclouds, providing us with chemical timestamps of the Galaxy.The detailed history of the Galactic disk and bulge is still to be untagled. LÄS MER