Conveners
Morning session
- Zsolt Fulop
Morning session
- Daniel Galaviz
Morning session
- Adriana Banu (James Madison University)
The production of the p-process nuclei in stars is still an open problem for nuclear astrophysics. Current supernova models seem to not produce enough of them, and their high abundances in the Solar System represent a challenge for stellar nucleosynthesis. Different scenarios have been proposed to solve these issues, but more work is needed. In this context, the p-process nuclei provide an...
The lack of knowledge of $\alpha$-nuclear potentials in unstable nuclei constitutes one of the main uncertainties associated to the modeling of the production of heavy p-nuclei [1,2]. Global parametrizations used to model the elastic scattering cross section of α particles on radioactive nuclei may differ up to a factor of 2, with a corresponding impact in the determination of...
The p-nuclei, rich in protons, are created through a specific nucleosynthesis process involving numerous reactions such as (γ, n), (γ, p), and (γ, α) in explosive astrophysical events like supernovae. The research aims to adjust astrophysical scenarios to replicate the observed abundances of these nuclei. A significant challenge in this research is the uncertainty in alpha-nucleus optical...
The existence of some stable neutron deficient nuclei - the p nuclei - can not be explained by neutron-capture processes [1]. Therefore, other types of reactions - dominantly photodisintegration reactions - come into play. This is called the $\gamma$ process. Statistical model calculations play a crucial role in modelling this process as cross sections for many of these photodisintegration...
Heterogeneities in the nucleosynthetic composition of meteorites for the p-nuclides are less common than for s-process isotopes and have been identified for 84Sr (e.g. Charlier et al., 2021), 144Sm (e.g. Andreasen and Sharma, 2006), 174Hf (Peters et al., 2017) and 180W (Cook et al., 2018). The origin of p-nuclide heterogeneity is unclear and is not related to specific presolar grains found in...
The astrophysical origins of the heaviest stable elements that we observe today in the Solar System are still not fully understood. Recent studies have demonstrated that H-accreting white dwarfs (WDs) in a binary system exploding as type Ia supernovae could be an efficient p-process source beyond iron. However, both observational evidence and stellar models challenge the required frequency of...
This presentation brings into focus $^{78,80}$Kr($\gamma$,$\gamma’$), $^{93}$Mo($\gamma$,n) and $^{90}$Zr($\gamma$,n) cross section measurements carried out using real photons at the HIGS/TUNL facility. The overarching physics motivation for these experimental investigations is to advance knowledge on a forefront topic in nuclear astrophysics – the nucleosynthesis beyond Fe of the rarest...
In this talk, I will show the SIMPLE python code we have developed and its capabilities. The code allows us to use 6 different sets of core-collapse supernova model sets with 15, 20 and 25 solar mass progenitors in order to compare the nucleosynthesis process data from the simulated supernova models with the isotope ratios measured from meteorites. The main objective of the code is to help...
Photonuclear reactions are critical in p-process nucleosynthesis, which produces rare proton-rich isotopes (p-nuclei) through γ-induced reactions like (γ, n), (γ, p), and (γ, α). These reactions occur at temperatures from 1.5 to 3.5 GK, typically in explosive environments such as ty-pe II or type Ia supernovae. Theoretical estimates of p-nuclei nucleosynthesis are uncertain, requiring accurate...
The heavier p-isotopes can be produced through the $\gamma$-process, which involves a complicated reaction network. In this nucleosynthesis process ($\gamma$,$\alpha$) reactions play a key role. To calculate such a reaction network, many input parameters are essential. One of these is the $\alpha$-nucleus optical model potential (AOMP), which describes the interaction between the $\alpha$...
Massive stars are thought to experience p-process nucleosynthesis when they explode as supernovae (and during their last hydrostatic burning stages to a smaller extent). Thanks to the mixing induced by rotational instabilities, rotating massive stars can experience an enhanced s-process during the core helium-burning phase. This can significantly affect the subsequent p-process during their...
The astrophysical p-process is crucial for the synthesis of proton-rich isotopes (p-nuclei) that cannot be formed via the s-process or r-process. Occurring primarily in supernovae, this process involves photodisintegration reactions like (γ, n), (γ, p) and (γ, α), driven by high-energy gamma photons, (p, γ) reactions are also relevant in this context. Recent experimental advances, including...
In massive-star binary systems, upon reaching later stages of stellar evolution one star can expand as a giant and envelope its companion in what is called a common envelope phase. The enveloped companion, here a neutron star, begins to accrete matter. The angular momentum of the accreting material results in the formation of an accretion disk. Accretion of hydrogen rich onto...
The High EffiCiency TOtal absorption spectrometeR (HECTOR) is a summing spectrometer comprised of 16 NaI(Tl) segmented crystals with 2 PMTs on each segment to allow for optimal light collection from incident $\gamma$-rays. The arrangement of the 16 NaI(Tl) crystals allows for almost total 4$\pi$ angular coverage to capture and sum together all $\gamma$-rays following the dexcitation of the...
Several species of short-lived radioactive nuclei (SLRs) are known to have been present in the early solar system (ESS). They are a valuable source of our knowledge of our solar system's formation and early history. Here, we present the latest results from the ERC RADIOSTAR project in a representation usually used in cosmochemistry, where the abundances of SLRs in the early solar system,...
Charge-Exchange (CE) reactions are an important tool for studying the spin-isopin response of nuclei. They can be utilized to obtain information about interactions mediated by the weak nuclear force, such as β and electron capture decay. Using the proportionality between Gamow-Teller strength (B(GT)) and the CE differential cross section, B(GT) distributions can be extracted indirectly. Since...
Thirty years ago, the pioneering experiment on $^{44}$Sm($\alpha$,$\gamma$)$^{148}$Gd by Somorjai $et$ $al.$ [1] (discussed first at a workshop in Budapest in 1994) showed that the prediction of astrophysical reaction rates of $\alpha$-induced reactions is very uncertain. The $\alpha$-nucleus potential (AOMP) was realized as the main source of the wide range of predictions. Only a few years...
Presolar stardust grains, bona-fide particles that formed in the death throes of dying stars and can today be extracted from meteorites, allow us to probe their parent star's isotopic composition. These grains are the sole messenger for directly probing the isotopic composition of the proton-rich isotopes associated with the p-process(es), since these isotopes generally only make up a minute...
