Hostname: page-component-78c5997874-4rdpn Total loading time: 0 Render date: 2024-11-11T02:53:16.352Z Has data issue: false hasContentIssue false
  • English
  • Français

What helium and lithium can tell us about CEMP stars?

Published online by Cambridge University Press:  23 April 2010

Georges Meynet ,
Raphael Hirschi ,
Sylvia Ekstrom ,
André Maeder ,
Cyril Georgy ,
Patrick Eggenberger  and
Cristina Chiappini
Georges Meynet
Affiliation:
Geneva Observatory, Geneva University, CH–1290 Sauverny, Switzerland email: georges.meynet@unige.ch
Raphael Hirschi
Affiliation:
Astrophysics group, Keele University, Lennard-Jones Lab., Keele, ST5 5BG, UK IPMU, University of Tokyo, Kashiwa, Chiba 277-8582, Japan
Sylvia Ekstrom
Affiliation:
Geneva Observatory, Geneva University, CH–1290 Sauverny, Switzerland email: georges.meynet@unige.ch
André Maeder
Affiliation:
Geneva Observatory, Geneva University, CH–1290 Sauverny, Switzerland email: georges.meynet@unige.ch
Cyril Georgy
Affiliation:
Geneva Observatory, Geneva University, CH–1290 Sauverny, Switzerland email: georges.meynet@unige.ch
Patrick Eggenberger
Affiliation:
Geneva Observatory, Geneva University, CH–1290 Sauverny, Switzerland email: georges.meynet@unige.ch
Cristina Chiappini
Affiliation:
Geneva Observatory, Geneva University, CH–1290 Sauverny, Switzerland email: georges.meynet@unige.ch
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We show that the peculiar surface abundance patterns of Carbon Enhanced Metal Poor (CEMP) stars has been inherited from material having been processed by H- and He-burning phases in a previous generation of stars (hereafter called the “Source Stars”). In this previous generation, some mixing must have occurred between the He- and the H-burning regions in order to explain the high observed abundances of nitrogen. In addition, it is necessary to postulate that a very small fraction of the carbon-oxygen core has been expelled (either by winds or by the supernova explosion). Therefore only the outermost layers should have been released by the Source Stars. Some of the CEMP stars may be He-rich if the matter from the Source Star is not too much diluted with the InterStellar Medium (ISM). Those stars formed from nearly pure ejecta would also be Li-poor.

Keywords

stars: AGBearly-typeevolution – supernovae: general – Galaxy: halo – nucleosynthesis
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S268: Light Elements in the Universe , November 2009 , pp. 141 - 146
Copyright
Copyright © International Astronomical Union 2010

References

Carollo, D., Beers, T. C., Lee, Y. S. et al. 2008, Nature, 451, 216Google Scholar
Chiappini, C., Ekström, S., Meynet, G. et al. 2008, A&A, 479, L9Google Scholar
Chiappini, C., Hirschi, R., Meynet, G. et al. 2006, A&A, 449, L27Google Scholar
Decressin, T., Meynet, G., Charbonnel, C., Prantzos, N., & Ekström, S. 2007, A&A, 464, 1029Google Scholar
Frebel, A., Collet, R., Eriksson, K., Christlieb, N., & Aoki, W. 2008, ApJ, 684, 588CrossRefGoogle Scholar
Hirschi, R. 2007, A&A, 461, 571Google Scholar
Korn, A. J., Richard, O., Mashonkina, L. et al. 2009, ApJ, 698, 410CrossRefGoogle Scholar
Lucatello, S., Beers, T. C., Christlieb, N. et al. 2006, ApJL, 652, L37CrossRefGoogle Scholar
Maeder, A. & Meynet, G. 2001, A&A, 373, 555Google Scholar
Maeder, A. & Meynet, G. 2006, A&A, 448, L37Google Scholar
Masseron, T., Johnson, J. A., Plez, B. et al. 2009, ArXiv e-prints 0901.4737Google Scholar
Meynet, G., Ekström, S., & Maeder, A. 2006, A&A, 447, 623Google Scholar
Meynet, G., Hirschi, R., Ekstrom, S. et al. 2009, ArXiv e-prints 0910.3856Google Scholar
Moehler, S., Sweigart, A. V., Landsman, W. B., & Heber, U. 2000, A&A, 360, 120Google Scholar
Spite, M., Cayrel, R., Hill, V. et al. 2006, A&A, 455, 291Google Scholar
Tominaga, N., Umeda, H., & Nomoto, K. 2007, ApJ, 660, 516CrossRefGoogle Scholar