The CH Stars. III. Heavy Element Abundances

Vanture, Andrew D.

doi:10.1086/116375

Cited by 78 publications

(84 citation statements)

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“…The pattern of abundance enhancements of the post-ironpeak elements in HD 35155 is similar to that seen in other yellow symbiotic stars (Smith et al 1996(Smith et al , 1997Pereira et al 1998), the post-AGB star FG Sge (Gonzalez & Wallerstein 1998), and the red giant CH stars (Vanture 1992). Such a pattern, in which the heavy s-process (hs) elements (Ba, La, Ce, Nd) are enhanced to a greater degree then the light s-process (ls) elements (Y, Zr), is a consequence of the efficient operation of the 13 C( , n) 16 O neutron source in lowto intermediate-mass stars (1.5-3.0 M ).…”

Section: Nucleosynthesis In Hd 35155supporting

confidence: 74%

Abundances of Post–Iron‐Peak Elements in HD 35155: A Symbiotic Star of Spectral Type S

Vanture

Wallerstein

Gallino

et al. 2003

ApJ

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We present abundances of Ti, Fe, and Ni as well as 10 post-iron-peak elements in the extrinsic, Galactic S star HD 35155. This star is of interest because it shows many characteristics of symbiotic stars and displays the same pattern of abundance enhancements observed in yellow symbiotic stars. It is clear that HD 35155 is associated with the symbiotic stars and provides an important link between the symbiotic phenomena and chemically peculiar stars. In addition, the abundance ratio of heavy to light s-process elements correlates with the metallicity of HD 35155, as is expected if the 13 C neutron source drives the s-process. Our models predict that the abundance of lead should be enhanced by a factor of between 50 to 500 in HD 35155.

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Section: Nucleosynthesis In Hd 35155supporting

confidence: 74%

Abundances of Post–Iron‐Peak Elements in HD 35155: A Symbiotic Star of Spectral Type S

Vanture

Wallerstein

Gallino

et al. 2003

ApJ

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“…More recent abundance analyses of CH-stars (Van Eck et al 2001;Van Eck et al 2003;Aoki et al 2001Aoki et al , 2002 confirmed the older results of Vanture (1992c), and focussed on the detection of an enhanced lead content, which was predicted in different nucleosynthetic AGB models (e.g. Gallino et al 1998;Goriely & Mowlavi 2000).…”

Section: Comparison With Galactic Ch Starsmentioning

confidence: 71%

AGB nucleosynthesis in the Large Magellanic Cloud

Reyniers¹,

Abia

Winckel³

et al. 2006

A&A

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Context. Abundance analysis of post-AGB objects as probes of AGB nucleosynthesis. Aims. A detailed photospheric abundance study is performed on the carbon-rich post-AGB candidate MACHO 47.2496.8 in the LMC. Methods. High-resolution, high signal-to-noise ESO VLT-UVES spectra of MACHO 47.2496.8 are analysed by performing detailed spectrum synthesis modelling using state-of-the-art carbon-rich MARCS atmosphere models. Results. The spectrum of MACHO 47.2496.8 is not only dominated by bands of carbon bearing molecules, but also by lines of atomic transitions of s-process elements. The metallicity of [Fe/H] = −1.4 is surprisingly low for a field LMC star. The C/O ratio, however difficult to quantify, is greater than 2, and the s-process enrichment is large: the light s-process elements are enhanced by 1.2 dex compared to iron ([ls/Fe] = +1.2), while for the heavy s-process elements an even stronger enrichment is measured: [hs/Fe] = +2.1. The lead abundance is comparable to the [hs/Fe]. With its low intrinsic metallicity and its luminosity at the low end of the carbon star luminosity function, the star represents likely the final stage of a low initial mass star. Conclusions. The LMC RV Tauri star MACHO 47.2496.8 is highly carbon and s-process enriched, and is most probable a genuine post-C(N-type) AGB star. This is the first detailed abundance analysis of an extragalactic post-AGB star to date.

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“…For barium giants the 12 C/ 13 C ratio lies between 8 and 20. For the CH stars, Vanture (1992c) showed that they could be divided into two groups, according to the 12 C/ 13 C ratio, some having 12 C/ 13 C ≈ 3.0 and others with 12 C/ 13 C ≥ 25.0. Inspecting Fig.…”

Section: C/ 13 C Ratiomentioning

confidence: 99%

High-resolution spectroscopic observations of two chemically peculiar metal-poor stars: HD 10613 and BD+04°2466

Pereira

Драке²

2009

A&A

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Aims. We determined the atmospheric parameters and abundance pattern of two chemically peculiar metal-poor stars: HD 10613 and BD+04 • 2466 in order to better understand their evolutionary state and the nature of the s-element enhancement of these stars. Methods. We used high resolution optical spectroscopy. Atmospheric parameters and abundances were determined in the localthermodynamic-equilibrium model atmospheres of Kurucz using the spectral analysis code MOOG. • 2466 the abundance of lead is in agreement with predictions from AGB models. Due to the low luminosity of these two stars, their observed s-process overabundance is better explained by mass-transfer in the past from an AGB star.

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The CH Stars. III. Heavy Element Abundances

Cited by 78 publications

References 0 publications

Abundances of Post–Iron‐Peak Elements in HD 35155: A Symbiotic Star of Spectral Type S

Abundances of Post–Iron‐Peak Elements in HD 35155: A Symbiotic Star of Spectral Type S

AGB nucleosynthesis in the Large Magellanic Cloud

High-resolution spectroscopic observations of two chemically peculiar metal-poor stars: HD 10613 and BD+04°2466

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