Abundance and Isotopic Anomalies of Thallium in the Atmosphere of the HgMn Star chi LUPI

Leckrone, D. S.; Johansson, Sveneric; Kalus, Gabriele; Wahlgren, G. M.; Brage, Tomas; Proffitt, Charles

doi:10.1086/177206

Cited by 25 publications

(11 citation statements)

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“…The atomic data (wavelengths, oscillator strengths, energy levels, isotopic shifts, and hyperfine structure) appropriate for the analysis of specific heavy element lines are taken from several studies that have already been published by us regarding the analysis of CP stars using Hubble Space Telescope spectra obtained with the Goddard High Resolution Spectrograph. These studies, including ions of platinum ( Wahlgren et al 1995;Kalus et al 1998), gold ( Wahlgren et al 1995), mercury ( Wahlgren et al 1995;Proffitt et al 1999), thallium Leckrone et al 1996), and bismuth ( Wahlgren et al 1994b( Wahlgren et al , 2001Henderson et al 1996;Dolk et al 2002), discuss problems associated with line blending as observed at high spectral resolution as well as the goodness and corrections of atomic data for lines blended with the ion lines of interest. The effects of hyperfine structure and isotopic shifts are also included into the heavy element atomic line data.…”

Section: Synthetic Spectramentioning

confidence: 99%

Heavy Element Abundances in Late‐B and Early‐A Stars. I. Co‐AddedIUESpectra of HgMn Stars

Adelman¹,

Proffitt²,

Wahlgren³

et al. 2004

ASTROPHYS J SUPPL S

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Very heavy elements ( Pt, Au, Hg, Tl, and Bi) are found to be enhanced in the atmospheres of the chemically peculiar stars of the upper main sequence by up to a million times the solar system levels. Such enhancements are believed to result from atmospheric dynamics (i.e., diffusion) rather than scenarios that dredge up nuclearprocessed material to the surface or transfer processed material between binary companions. However, the theoretical framework needs to be further constrained by observations beyond the realm of the spectral types for which such abundance enhancements are observed at optical wavelengths.The International Ultraviolet Explorer (IUE ) satellite collected spectra of bright stars for which chemical peculiarities have been derived from ground-based data. For several elements the abundance enhancements have only been recently measured using Hubble Space Telescope data and have therefore not yet been exploited in the IUE data. We have initiated a program to analyze IUE high-dispersion spectra to more fully characterize the pattern of very heavy element enhancement for many mercury-manganese ( HgMn) stars and to potentially extend the spectral class (effective temperature) boundaries over which these abundance anomalies are known to exist. The abundances of very heavy elements in chemically normal B and A-type stars provide a base level that may be compared with the solar system abundances. These early spectral type stars may therefore reveal clues for galactic chemical evolution studies since they were formed at a later epoch than the Sun in the history of the Galaxy. This first paper presents the motivation for the analyses to follow, outlines our spectral co-addition technique for IUE spectra, and discusses the choice of model atmospheres and the synthetic spectrum procedures, while initiating the study by highlighting the abundance of gold in several HgMn stars.

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Section: Synthetic Spectramentioning

confidence: 99%

Heavy Element Abundances in Late‐B and Early‐A Stars. I. Co‐AddedIUESpectra of HgMn Stars

Adelman¹,

Proffitt²,

Wahlgren³

et al. 2004

ASTROPHYS J SUPPL S

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“…Recent theoretical work by Seaton (1997Seaton ( , 1999 has addressed the behavior of iron group elements in unevolving models. Other modeling e †orts (Proffitt et al 1999 ;Leckrone et al 1996) have been unable to maintain the great line enhancements over extended periods of time. Thus, temporal evolution may enter into the problem in presently unknown ways.…”

Section: Introductionmentioning

confidence: 99%

The Bismuth Abundance in the HgMn Stars χ Lupi and HR 7775 and Improved Atomic Data for Selected Transitions of Bii, Biii, and Biiii

Wahlgren

Brage

Brandt

et al. 2001

ApJ

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High-resolution spectra of the chemically peculiar HgMn stars s Lupi and HR 7775, obtained with the Hubble Space T elescope/Goddard High Resolution Spectrograph, are investigated for their abundance of bismuth by comparison with LTE synthetic spectrum modeling. HR 7775, previously known from International Ultraviolet Explorer spectra to display strong lines of Bi II, is determined to have bismuth present at an enhancement level of nearly 5 orders of magnitude from the lines Bi II jj1436, 1902 and Bi III j1423. The bismuth enhancement for s Lupi is found to be near a level of 1.5 dex, and an ionization anomaly between Bi`and Bi``is apparent. HR 7775 abundance enhancements of the heavy elements platinum, [Pt/H] \ 4.7 dex, and gold, [Au/H] \ 3.8 dex, have also been determined. New laboratory measurements for wavelengths and hyperÐne structure patterns of Bi I/Bi II/Bi III lines are presented, as well as the results of calculations for hyperÐne structure constants and oscillator strengths for selected lines of Bi II and Bi III.

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“…(Smith & Dworetsky 1993;Smith 1993Smith , 1994Smith , 1996aSmith , 1996bSmith , 1997. Recent observations show strongly anomalous isotopic composition for Hg, Pt, Tl (overabundancy of heavier isotopes) and He (overabundancy of He) (Cowley & Aikman 1975;Kalus et al 1998;Leckrone et al 1996;Proffitt et al 1999;White et al 1976). In the present paper we analyze the generation of isotopic anomalies for mercury in the atmospheres of mercury-manganese Correspondence to: Anna Aret, aret@aai.ee (HgMn) stars due to light-induced drift, radiative force and gravity.…”

Section: Introductionmentioning

confidence: 99%

Light-induced drift for Hg isotopes in chemically peculiar stars

Aret

Sapar

2002

Astron. Nachr.

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Abundance and Isotopic Anomalies of Thallium in the Atmosphere of the HgMn Star chi LUPI

Cited by 25 publications

References 0 publications

Heavy Element Abundances in Late‐B and Early‐A Stars. I. Co‐AddedIUESpectra of HgMn Stars

Heavy Element Abundances in Late‐B and Early‐A Stars. I. Co‐AddedIUESpectra of HgMn Stars

The Bismuth Abundance in the HgMn Stars χ Lupi and HR 7775 and Improved Atomic Data for Selected Transitions of Bii, Biii, and Biiii

Light-induced drift for Hg isotopes in chemically peculiar stars

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