Speaker
Description
In a large-scale nucleosynthesis parameter study, we have extended the initial ideas of Hoffman et al. [1], who showed that light p-nuclei can be produced in the neutrino-driven winds of core-collapse supernovae (cc-SNe). Our project began about a decay ago, based on the r-process model of Farouqi et al. [2], where we found that in the low-entropy (S) charged-particle component of moderately neutron-rich wind ejecta of cc-SNe, in addition to the classical light „p-only“ isotopes, the „s-only“ and „r-only“ nuclei between Zn (Z = 30) and Pd (Z = 46) can also be co-produced [3,4]. In the present contribution, we focus on a recent update to the nucleosynthetic interpretation of the anomalous isotopic compositions of Zr (Z = 40; 5 stable isotopes), Mo (Z = 42; 7 stable isotopes) and Ru (Z= 44; 7 stable isotopes) reported in the rare presolar SiC-X grains discovered by the Argonne/Chicago group [5]. In contrast to the dominant class of AGB (s-process) grains, very few SiC-X grains were identified and qualitatively interpreted to originate from explosive nucleosynthesis scenarios. We show that these meteoritic observations do not represent the signatures of a „clean“ stellar scenario, but rather are mixtures of an exotic nucleosynthesis component with different fractions of Solar System material [6,7]. The co-production of these isotopes through a rapid „primary“ production mode provides further means to revise the abundance estimates of the light trans-Fe elements from so far favoured „secondary“ nucleosynthesis scenarios like Type Ia SNe (see, e.g. [8]) or neutron-bursts in exploding massive stars [9]. Finally, we point out that from the isotopic abundance patterns of the SiC-X grains, we obtain better electron fraction - entropy ($Y_e - S$) constraints for nucleosynthesis in regular cc-SNe nucleosynthesis than we do from the elemental abundances of metal-poor halo stars [10].
References:
[1] R.D. Hoffman et al.; Ap.J. 460, 478 (1996)
[2] K. Farouqi et al.; Ap.J. 712, 1359 (2010)
[3] K. Farouqi, K.-L. Kratz & B. Pfeiffer; PASA 26, 194 (2009)
[4] K. Farouqi et al.; NIC XI, PoS (2010)
[5] M.J. Pellin et al., LPSC 31, 1917 (2000); and LPSC 37, 2041 (2006)
[6] K.-L. Kratz et al.; AIP Conf. Proc. 2076, 030002 (2019)
[7] W. Akram et al.; EPJ Web Conf. 227, 01009 (2020)
[8] C. Travaglio et al.; ApJ 739, 93 (2011)
[9] M. Howard et al.; Meteoritics 27, 404 (1992)
[10] K. Farouqi et al.; Astronomy & Astrophysics, https://doi.org/10.1051/0004-6361/202141038
| Session | Dust and presolar grains |
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