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Title: The chemical composition of ρ puppis and the signs of accretion in the atmospheres of B–F-type stars

We investigated the chemical composition of ρ Pup using high-resolution spectral observations taken from the Very Large Telescope and the IUE archives and also spectra obtained at the 1.8 m telescope of the Bohyunsan observatory in Korea. The abundances of 56 chemical elements and the upper limits of Li and Be abundances were determined. The abundance pattern of ρ Pup was found to be similar to that of Am-type stars. The possibility of the influence of the accretion of interstellar gas and dust on the abundance patterns of B–F-type stars is discussed. The plots of the relative abundances of chemical elements in the atmospheres of ρ Pup and δ Sct versus the second ionization potentials of these elements show the correlations. The discontinuities at 13.6 and 24.6 eV—the ionization potentials of hydrogen and helium, respectively, are also exhibited in these plots. These discontinuities can be explained by interaction of the atoms of interstellar gas, mainly hydrogen and helium atoms, with the atoms of stellar photospheres (so-called charge-exchange reactions). Note that only the jumps near 13.6 and 24.6 eV were pointed out in previous investigations of relative abundances versus the second ionization potentials for Am-type stars. The dependencies of the relativemore » abundances of chemical elements on the second ionization potentials of these elements were investigated using the published abundance patterns of B–F-type stars. The correlations of relative and absolute abundances of chemical elements, second ionization potentials, and projected rotational velocities are clearly detected for stars with effective temperatures between 7,000 and 12,000 K. If the correlation of relative abundances and second ionization potentials can be explained by the accretion of interstellar gas on the stellar surfaces, the investigation of these correlations can provide valuable information on the density and velocities of interstellar gas in different regions of the Galaxy and also on the influence of this phenomenon on stellar evolution. The dependencies of the relative abundances of chemical elements on the condensation temperatures of these elements were also found in the atmospheres of ρ Pup, δ Sct, and other B–F-type stars. Ten possible λ Boo-type stars were detected. The effective temperatures of these objects are between 10,900 and 14,000 K.« less
Authors:
; ; ; ;  [1] ; ; ;  [2] ;  [3] ; ;  [4] ;  [5] ;  [6]
  1. Department of Astronomy and Space Science, Sejong University, Seoul, 143-747 (Korea, Republic of)
  2. Astronomical observatory, Odessa National University, Odessa, 65014 (Ukraine)
  3. Division of Science Education, Institute of Science Education, and Institute of Fusion Science, Chonbuk National University, Chonju 561-756 (Korea, Republic of)
  4. Korea Astronomy and Space Science Institute, Daejon 305-348 (Korea, Republic of)
  5. Department of physics, Odessa National Maritime University, 65029, Odessa (Ukraine)
  6. Seoul National University, Seoul 151-742 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22342116
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 149; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; ACCRETION DISKS; ATOMS; CHARGE-EXCHANGE REACTIONS; CORRELATIONS; DENSITY; GALAXIES; HELIUM; INTERACTIONS; PHOTOSPHERE; RESOLUTION; ROTATION; SPECTRA; STAR EVOLUTION; STARS; SURFACES; TELESCOPES; VELOCITY