Thorium-rich halo star HD 221170: Further evidence against  
 the universality of the r-process

Yushchenko, A. V.; Gopka, V. F.; Goriely, Stéphane; Мусаев, Ф. А.; Шаврина, А. В.; Kim, C.; Kang, Yong; Kuznietsova, J.; Yushchenko, V. A.

doi:10.1051/0004-6361:20041540

Cited by 25 publications

(52 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Fe and Ba abundance distributions agree with those derived previously by either trial-and-error method (Ryabchikova 2003) or based on the equivalent widths (Yushchenko et al 2007). Figures 4−7 (Online material) illustrate the resulting fit to line profiles.…”

Section: Abundance Patternsupporting

confidence: 87%

Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065

Shulyak

Ryabchikova

Kildiyarova

et al. 2010

A&A

View full text Add to dashboard Cite

Aims. Among the known Ap stars, HD 101065 is probably one of the most interesting objects, demonstrating very rich spectra of rareearth elements (REE). Strongly peculiar photometric parameters of this star can not be fully reproduced by any modern theoretical calculations, even those accounting for realistic chemistry of its atmosphere. In this study we investigate a role of missing REE line opacity and construct a self-consistent atmospheric model based on accurate abundance and chemical stratification analysis. Methods. We employed the LLmodels stellar model atmosphere code together with DDAFit and Synthmag software packages to derive homogeneous and stratified abundances for 52 chemical elements and to construct a self-consistent model of HD 101065 atmosphere. The opacity in REE lines is accounted for in details, by using up-to-date extensive theoretical calculations. Results. We show that REE elements play a key role in the radiative energy balance in the atmosphere of HD 101065, leading to the strong suppression of the Balmer jump and energy redistribution very different from that of normal stars. Introducing new line lists of REEs allowed us to reproduce, for the first time, spectral energy distribution of HD 101065 and achieve a better agreement between the unusually small observed Strömgren c 1 index and the model predictions. Using combined photometric and spectroscopic approaches and based on the iterative procedure of abundance and stratification analysis we find effective temperature of HD 101065 to be T eff = 6400 K.

show abstract

Section: Abundance Patternsupporting

confidence: 87%

Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065

Shulyak

Ryabchikova

Kildiyarova

et al. 2010

A&A

View full text Add to dashboard Cite

show abstract

“…Plez et al (2004) have derived a Pb abundance that seems to be too low with respect to such high abundance values of radioactive elements Th and U (Kratz et al 2004). Some reports of high Th/Eu abundance ratios in other stars (e.g., Yushchenko et al 2005) have been revised significantly downward upon reanalysis with better stellar spectroscopic and atomic data (Ivans et al 2006).…”

Section: Nucleocosmochronometrymentioning

confidence: 99%

Neutron-Capture Elements in the Early Galaxy

Sneden

Cowan²,

Gallino

2008

Annu. Rev. Astron. Astrophys.

906

1,215

View full text Add to dashboard Cite

The content of neutron-capture (trans-iron-peak) elements in the lowmetallicity Galactic halo varies widely from star to star. The differences are both in bulk amount of the neutron-capture elements with respect to lighter ones and in element-to-element ratios among themselves. Several well-defined abundance distributions have emerged that reveal characteristic rapid and slow neutron-capture nucleosynthesis patterns. In this review we summarize these observed metal-poor star's abundances, contrasting them with the Solar-system values, comparing them to theoretical predictions, using them to assess the types of stars responsible for their specific anomalies, and speculating on the timing and nature of early Galactic nucleosynthesis. 241 Annu. Rev. Astro. Astrophys. 2008.46:241-288. Downloaded from www.annualreviews.org by Carleton University (Canada) on 09/20/13. For personal use only.

show abstract

“…For comparison purposes, we also observed the bright halo red giant HD 221170. This comparison star is known to have a moderate enhancement of r-process elements (Yushchenko et al 2005).…”

Section: Observationsmentioning

confidence: 99%

Neutron-Capture Elements in the Metal-poor Globular Cluster M15

Otsuki

Honda

Aoki

et al. 2006

ApJ

View full text Add to dashboard Cite

We report on observations of six giants in the globular cluster M15 (NGC 7078) using the Subaru Telescope to measure neutron-capture elemental abundances. Our abundance analyses, based on high-quality blue spectra, confirm the star-to-star scatter in the abundances of heavy neutron-capture elements (e.g., Eu), and we found no significant s-process contribution to them, as was found in previous studies. We have found that, for the first time, there are anticorrelations between the abundance ratios of light to heavy neutron-capture elements ([Y/Eu] and [Zr/Eu]) and the heavy neutron-capture elements (e.g., Eu). This indicates that the light neutron-capture elements in these stars cannot be explained by only a single r-process. Another process that contributed significantly to the light neutroncapture elements is required in M15. Our results suggest a complicated enrichment history for M15 and its progenitor.

show abstract

Thorium-rich halo star HD 221170: Further evidence against the universality of the r-process

Cited by 25 publications

References 26 publications

Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065

Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065

Neutron-Capture Elements in the Early Galaxy

Neutron-Capture Elements in the Metal-poor Globular Cluster M15

Contact Info

Product

Resources

About