Title

The 33S(p,γ)34Cl reaction in classical nova explosions

Authors

Anuj Parikh, Fakultät für Physik, Technische Universität München
Thomas Faestermann, Fakultät für Physik, Technische Universität München
Reiner Krüken, Fakultät für Physik, Technische Universität München
Vinzenz Bildstein, Fakultät für Physik, Technische Universität München
Shawn Bishop, Fakultät für Physik, Technische Universität München
Katrin Eppinger, Fakultät für Physik, Technische Universität München
Clemens Herlitzius, Fakultät für Physik, Technische Universität München
Olga Lepyoshkina, Fakultät für Physik, Technische Universität München
Peter Maierbeck, Fakultät für Physik, Technische Universität München
Dominik Seiler, Fakultät für Physik, Technische Universität München
Kathrin Wimmer, Fakultät für Physik, Technische Universität München
Ralf Hertenberger, Ludwig-Maximilians-Universität München
Hans Friedrich Wirth, Ludwig-Maximilians-Universität München
Jennifer Fallis, TRIUMF
Ulrike Hager, TRIUMF
David Hutcheon, TRIUMF
Chris Ruiz, TRIUMF
Lothar Buchmann, TRIUMF
Dave Ottewell, TRIUMF
Blake Freeman, University of Washington
Chris Wrede, University of Washington
Alejandro García, University of Washington
Brent Delbridge, University of Washington
Andreas Knecht, University of Washington
Anne Sallaska, University of Washington
Alan A. Chen, Excellence Cluster ORIGINS
Jason A. Clark, Argonne National Laboratory
Catherine M. Deibel, Argonne National Laboratory
Brian Fulton, University of York
Alison Laird, University of York
Uwe Greife, Colorado School of Mines
Bing Guo, China Institute of Atomic Energy
Er Tao Li, China Institute of Atomic Energy

Document Type

Conference Proceeding

Publication Date

12-1-2010

Abstract

The analysis of microscopic grains within primitive meteorites has revealed isotopic ratios largely characteristic of the conditions thought to prevail in various astrophysical environments. Recently, several grains have been identified with isotopic signatures similar to those predicted within the ejecta of nova explosions on oxygen-neon white dwarfs. A possible smoking gun for a grain of nova origin is a large 33S abundance: nucleosynthesis calculations predict as much as 150 times the solar abundance of 33S in the ejecta of oxygen-neon novae. This overproduction factor may, however, vary by factors of at least 0.01 - 3 because of uncertainties in the 33S(p,γ)34Cl reaction rate over nova temperatures. In addition, better knowledge of this rate would help with the interpretation of nova observations over the S-Ca mass region, and contribute towards the firm establishment of a nucleosynthetic endpoint in these phenomena. Finally, constraining this rate may help to finally confirm or rule out the decay of an isomeric state of 34Cl (Ex = 146 keV, t1/2 =32 min) as a source for observable gamma-rays from novae. Direct examinations of the 33S(p,γ)34Cl reaction in the past have only identified resonances down to Er = 434 keV. At nova temperatures, lower-lying resonances could certainly play a dominant role. Several recent, complementary studies dedicated to improving our knowledge of the 33S(p,γ)34Cl rate, using both indirect methods (measurement of the 34S( 3He,t)34Cl and 33S(3He,d) 34Cl reactions with the Munich Q3D spectrograph) and direct methods (in normal kinematics at CENPA, University of Washington, and in inverse kinematics with the DRAGON recoil mass separator at TRIUMF) are presented here. Our results affect predictions of sulphur isotopic ratios in nova ejecta (e.g. 32S/33S) that may be used as diagnostic tools for the nova paternity of grains. © ?Copyright owned by the author(s).

Publication Source (Journal or Book title)

Proceedings of Science

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