Reaction rate sensitivity of 44Ti production in massive stars and implications of a thick target yield measurement of 40Ca(alpha,gamma)44Ti

Hoffman, R. D. and Sheets, S. A. and Burke, J. T. and Scielzo, N. D. and Rauscher, T. and Norman, E. B. and Tumey, S. and Brown, T. A. and Grant, P. G. and Hurst, A. M. and Phair, L. and Stoyer, M. A. and Wooddy, T. and Fisker, J. L. and Bleuel, D.. (2010) Reaction rate sensitivity of 44Ti production in massive stars and implications of a thick target yield measurement of 40Ca(alpha,gamma)44Ti. The astrophysical journal. Part 1, Vol. 715, H. 2. pp. 1383-1399.

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Official URL: http://edoc.unibas.ch/dok/A5840153

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We evaluate two dominant nuclear reaction rates and their uncertainties that affect Ti-44 production in explosive nucleosynthesis. Experimentally we develop thick target yields for the Ca-40(alpha, gamma)Ti-44 reaction at E alpha = 4.13, 4.54, and 5.36 MeV using gamma-ray spectroscopy. At the highest beam energy, we also performed an activation measurement which agrees with the thick target result. From the measured yields a stellar reaction rate was developed that is smaller than current statistical-model calculations and recent experimental results, which would suggest lower Ti-44 production in scenarios for the alpha-rich freezeout. Special attention has been paid to assessing realistic uncertainties of stellar reaction rates produced from a combination of experimental and theoretical cross sections. With such methods, we also develop a re-evaluation of the Ti-44(alpha, p)V-47 reaction rate. Using these two rates we carry out a sensitivity survey of Ti-44 synthesis in eight expansions representing peak temperature and density conditions drawn from a suite of recent supernova explosion models. Our results suggest that the current uncertainty in these two reaction rates could lead to as large an uncertainty in Ti-44 synthesis as that produced by different treatments of stellar physics.
Faculties and Departments:05 Faculty of Science > Departement Physik > Former Organization Units Physics > Theoretische Physik Astrophysik (Thielemann)
UniBasel Contributors:Rauscher, Thomas
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:University of Chicago Press
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:27 Mar 2014 13:12
Deposited On:14 Sep 2012 06:47

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