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GHRS spectroscopy of chemically peculiar stars: The chi Lupi Pathfinder Project

Leckrone, DS; Johansson, Sveneric LU ; Wahlgren, Glenn LU ; Proffitt, CR and Brage, Tomas LU (1998) Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph In The Scientific Impact of the Goddard High Resolution Spectrograph (Astronomical Society of the Pacific Conference Series) 143. p.135-153
Abstract
The HST has provided visual images of the universe of unprecedented clarity and sensitivity. It is less widely known that the HST/GHRS has provided equally breathtaking views of a different kind Of "universe" - a "spectroscopic universe". Nowhere is this better seen than in the extraordinarily complex and beautiful ultraviolet spectrum of the ultra-sharp-lined, non-magnetic, chemically peculiar (CP) star chi Lupi (B9.5pHgMn + A2 Vm). We have begun a systematic exploration and quantitative analysis of this spectrum with the echelle mode of the GHRS. We call this the "The chi Lupi Pathfinder Project", because it is analogous to the exploration and mapping of a previously uncharted land by a diverse team of specialists - in this case... (More)
The HST has provided visual images of the universe of unprecedented clarity and sensitivity. It is less widely known that the HST/GHRS has provided equally breathtaking views of a different kind Of "universe" - a "spectroscopic universe". Nowhere is this better seen than in the extraordinarily complex and beautiful ultraviolet spectrum of the ultra-sharp-lined, non-magnetic, chemically peculiar (CP) star chi Lupi (B9.5pHgMn + A2 Vm). We have begun a systematic exploration and quantitative analysis of this spectrum with the echelle mode of the GHRS. We call this the "The chi Lupi Pathfinder Project", because it is analogous to the exploration and mapping of a previously uncharted land by a diverse team of specialists - in this case astrophysicists and atomic physicists working synergistically. Our objective is to characterize, comprehensively and accurately, the full range of abundance and isotopic anomalies found in the atmosphere of at least one CP star to test and constrain the most widely accepted theoretical scenario for the production of abundance anomalies - radiatively-driven diffusion and gravitational settling. These physical mechanisms are important in several other astrophysical contexts. The surface layers of the CP stars provide a laboratory to investigate the conditions which foster them and the competing mechanisms which retard them. The GHRS echelle data set for chi Lupi covers 345 Angstrom, with S/N approximate to 50-100. We have quadrupled the number of elements for which abundances have been measured in this star, spanning most of the periodic table. These include several elements which have rarely, if ever, been seen before in a star other than the Sun and several examples of isotopically anomalous abundances. We have found systematic trends in these abundance data, which qualitatively support the mechanism of radiatively-driven diffusion and gravitational settling. However, our state-of-the-art theoretical, non-LTE diffusion models have not as yet been successful in sustaining the observed magnitudes of the largest abundance anomalies nor in reproducing anomalous isotope blends. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
in
The Scientific Impact of the Goddard High Resolution Spectrograph (Astronomical Society of the Pacific Conference Series)
volume
143
pages
135 - 153
publisher
Astronomical Society of the Pacific
conference name
Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph
external identifiers
  • WOS:000076566800011
ISBN
1-886733-63-5
language
English
LU publication?
yes
id
f68fdb8f-c9b0-4640-af55-6fcd3ecb5cc9 (old id 3919537)
date added to LUP
2013-07-09 08:20:24
date last changed
2016-04-16 10:25:30
@misc{f68fdb8f-c9b0-4640-af55-6fcd3ecb5cc9,
  abstract     = {The HST has provided visual images of the universe of unprecedented clarity and sensitivity. It is less widely known that the HST/GHRS has provided equally breathtaking views of a different kind Of "universe" - a "spectroscopic universe". Nowhere is this better seen than in the extraordinarily complex and beautiful ultraviolet spectrum of the ultra-sharp-lined, non-magnetic, chemically peculiar (CP) star chi Lupi (B9.5pHgMn + A2 Vm). We have begun a systematic exploration and quantitative analysis of this spectrum with the echelle mode of the GHRS. We call this the "The chi Lupi Pathfinder Project", because it is analogous to the exploration and mapping of a previously uncharted land by a diverse team of specialists - in this case astrophysicists and atomic physicists working synergistically. Our objective is to characterize, comprehensively and accurately, the full range of abundance and isotopic anomalies found in the atmosphere of at least one CP star to test and constrain the most widely accepted theoretical scenario for the production of abundance anomalies - radiatively-driven diffusion and gravitational settling. These physical mechanisms are important in several other astrophysical contexts. The surface layers of the CP stars provide a laboratory to investigate the conditions which foster them and the competing mechanisms which retard them. The GHRS echelle data set for chi Lupi covers 345 Angstrom, with S/N approximate to 50-100. We have quadrupled the number of elements for which abundances have been measured in this star, spanning most of the periodic table. These include several elements which have rarely, if ever, been seen before in a star other than the Sun and several examples of isotopically anomalous abundances. We have found systematic trends in these abundance data, which qualitatively support the mechanism of radiatively-driven diffusion and gravitational settling. However, our state-of-the-art theoretical, non-LTE diffusion models have not as yet been successful in sustaining the observed magnitudes of the largest abundance anomalies nor in reproducing anomalous isotope blends.},
  author       = {Leckrone, DS and Johansson, Sveneric and Wahlgren, Glenn and Proffitt, CR and Brage, Tomas},
  isbn         = {1-886733-63-5},
  language     = {eng},
  pages        = {135--153},
  publisher    = {ARRAY(0x9f6a708)},
  series       = {The Scientific Impact of the Goddard High Resolution Spectrograph (Astronomical Society of the Pacific Conference Series)},
  title        = {GHRS spectroscopy of chemically peculiar stars: The chi Lupi Pathfinder Project},
  volume       = {143},
  year         = {1998},
}