Conveners
Plenary Session: A: Neutron capture processes (1). & The early Universe (1).
- Eliana Masha (Helmholtz-Zentrum Dresden-Rossendorf e.V. (HZDR))
Plenary Session: B: Neutron capture processes (2). & Neutron stars (1).
- Cristina Chiappini (Karte von Leibniz-Institut für Astrophysik Potsdam Leibniz-Institut für Astrophysik Potsdam)
Plenary Session: C: Hydrostatic stellar burning (1).
- Alessandra Fantoni (European Physical Society)
Plenary Session: D: Dense matter (1). & New tools and techniques (1).
- Alison Laird (University of York)
Plenary Session: E: Explosive processes (1).
- Anton Wallner (HZDR)
Plenary Session: F: New tools and techniques (2). & Big Bang Nucleosynthesis (1).
- David Blaschke
Plenary Session: G: Cosmochemistry and Galactic Chemical Evolution (1).
- Günther Hasinger (Deutsches Zentrum für Astrophysik)
Plenary Session: H: Neutron capture processes (3).
- Raphael Hirschi (Keele University)
Plenary Session: I: Neutron capture processes (4). & New tools and techniques (3).
- Beatriz Jurado
Plenary Session: J: New tools and techniques (4).
- Almudena Arcones (TU Darmstadt)
Plenary Session: K: Cosmochemistry and Galactic Chemical Evolution (2). & Gravitational waves (1).
- Artemis Spyrou (Michigan State University)
Plenary Session: L: Neutron stars (2). & Explosive processes (2).
- Jenny Feige
Plenary Session: M: Neutron star (3). & New tools and techniques (5).
- François de Oliveira
Plenary Session: N: Neutron stars (4). & Explosive processes (3).
- Zsolt Podolyák (University of Surrey)
Plenary Session: O: Hydrostatic stellar burning (2).
- Alba Formicola
Plenary Session: P: Explosive processes (4). & Neutron Capture processes (5).
- György Gyürky (HUN-REN Institute for Nuclear Research)
Understanding the origin of the elements has been a decades-long pursuit, with many open questions remaining. Old stars found in the Milky Way and its dwarf satellite galaxies can provide answers because they preserve clean element abundance patterns of the nucleosynthesis processes that operated some 13 billion years ago, enabling reconstruction of the chemical evolution of the elements. This...
Despite considerable progresses during the last decades, the origin of the elements heavier than iron is not yet fully understood. In addition to the slow (s) and rapid (r) neutron capture processes, an intermediate neutron capture process (i-process) is thought to exist at neutron densities intermediate between the s- and r-processes. The astrophysical site(s) hosting the i-process is (are)...
The most iron-poor stars are thought to be among the oldest objects observable in the sky.
Understanding them provides us a deeper knowledge on formation and evolution of the pristine universe.
In fact, they are supposed to be formed from a gas enriched just by the explosion of the first generation of massive stars.
Their chemical inventory has the signature of the nucleosynthesis both...
New rotating stellar models for the first generations of massive stars will be presented. Their results on nucleosynthesis will be compared with observed composition of very iron-poor stars and with the composition recently inferred by spectroscopy in high redshift galaxies by the JWST. We shall show that both fast-rotating Population III stars and/or non-rotating very massive stars up to...
There are three “families” of nuclides with a particular value for s-process studies: s-only nuclei, bottlenecks and branchings. Interestingly, for none of them is the situation satisfactory from an experimental standpoint.
This contribution summarizes selected examples utilizing the time-of-flight technique at CERN n_TOF in combination with detection systems, which have been progressively...
More than 50 years after the discovery of neutrons stars, their interior composition and structure remain unknown. Because the extreme densities and matter asymmetry in neutron star interiors are out of reach for Earth laboratories, the equation of state of bulk nuclear matter is unknown, and its determination would have implication for astrophysics and nuclear physics. Thankfully,...
Active nucleosynthesis in our galaxy can be observed directly through the detection of long-lived radioactivities. Isotopes such as $^{26}$Al, and $^{60}$Fe have been observed either in solar system samples or through $\gamma$-ray observations within the galaxy. Both isotopes are predominantly produced in massive stars and ejected into the interstellar medium either via stellar winds or...
The most massive stars provide an essential source of recycled material for young clusters and galaxies. While very massive stars (VMS, $M>100 \,M_\odot$) are relatively rare compared to O stars, they lose disproportionately large amounts of mass already from the onset of core H-burning. In this talk, I will discuss the impact of stellar wind yields from VMS, calculated for a wide range of...
The chemical compositions of stars place key constraints on nuclear astrophysics. The most precise way of determining these compositions is through analyses of the absorption lines in the observed star light (stellar spectroscopy). However, the accuracy of standard analyses of Sun-like stars can be limited by various simplifying assumptions. The vast majority of analyses take the atmosphere...
During the last 30 years, the Laboratory for Underground Nuclear Astrophysics (LUNA) investigated many nuclear reactions of interest for cosmological and stellar models, often directly at the relevant Astrophysical energies. Nuclear reactions involved in the Big Bang nucleosynthesis, the p-p and CNO chains, as well as slow neutron capture were studied providing accurate and precise data to the...
The NeNa-MgAl cycles are involved in the synthesis of Ne, Na, Mg, and Al isotopes. The ${}^{20}\mathrm{Ne}(p,\gamma){}^{21}\mathrm{Na}$ reaction is the slowest reaction of the NeNa cycle and it controls the speed at which the entire cycle proceeds. The ${}^{21}\mathrm{Ne}(p,\gamma){}^{22}\mathrm{Na}$ has a relevant role in the production of the radioactive isotope ${}^{22}\mathrm{Na}$ that is...
The determination of the equation of state (EoS) of dense matter is a challenge in nuclear astrophysics, and particularly for the modelling of compact obects such as supernovae and neutron stars (NSs). Indeed, a consistent description of the different states of matter encountered in these stellar objects spanning a wide range of densities, temperatures, and isospin asymmetries is a difficult...
The gamma-ray decay of nuclear states in the quasi-continuum provides significant constraints on nucleosynthesis processes. In particular, measurements of Nuclear Level Densities (NLDs) and Photon Strength Functions (PSFs) have and will continue to play a central role as these are inputs for the statistical Hauser-Feshbach model. This facilitates the extraction of neutron-capture cross-section...
Over the past decades nuclear physicists have been trying to measure the rates of the most relevant nuclear reactions, which are responsible for the element nucleosynthesis, but there is still considerable uncertainty about their values.
This is because their reaction rates are extremely small, making it difficult for them to be measured directly in the laboratory. Indeed, although e.g. the...
We study the impact of asymmetric fermionic and bosonic dark matter on neutron star properties, including tidal deformability, maximum masses, radii, thermal evolution, a moment of inertia, quasi-universal relations, etc. The conditions at which dark matter particles tend to condense in the core of the star or create an extended halo are presented. We show that dark matter condensed in a core...
The nuclear symmetry energy and its density dependence play a crucial role in defining the properties of a wide range of systems, spanning from asymmetric nuclei to neutron stars and various other astrophysical phenomena. Motivated by recent advancements, particularly the precise determination of neutron skin thickness for ${}^{208}\mathrm{Pb}$ and ${}^{48}\mathrm{Ca}$ nuclei through PREX-II...
Explosive stellar environments such as novae, supernovae, x-ray bursts and neutron star mergers have been identified as possible candidate sites where the majority of the heavy elements are synthesized. Understanding the underlying mechanisms of the explosions can help to shed light on the observed chemical abundances at these sites. Accurate theoretical models of these environments can be...
Currently, the explanation behind the explosion mechanism of core collapse supernovae is yet to be fully understood. New insight to this phenomena may come through observations of $^{44}$Ti cosmic $\gamma$ rays; this technique compares the observed flux of cosmic $^{44}$Ti $\gamma$ rays to that predicted by state-of-the-art models of supernova explosions. In doing so, the mass cut point of the...
New models of so-called electron-capture supernovae (ECSNe) suggest that while the full collapse of sAGB stars to a NS is still a possibility, the energy release by the electron-capture reactions can also trigger a thermonuclear runaway initiating explosive thermonuclear burning in a ''thermonuclear ECSN'' (tECSN).
Initial studies suggest that tECSNe could reproduce the solar abundances of so...
Magnetorotational supernovae are hypothesized as environments for the rapid neutron-capture process (r-process) responsible for the formation of heavy elements in our Universe. The magnetic fields within these events are a key ingredient in this process, yet their precise strength and configuration remain elusive. To address this, we analyzed comprehensive 3D MHD supernova simulations with...
Massive stars (>10M☉) undergo core-collapse supernova explosions at the end of evolution. These explosions release elements ranging from helium (produced during the stellar evolution) to iron peak synthesized in explosive nucleosynthesis. Although the explosion mechanism of core-collapse supernovae is not fully understood, 1D spherically symmetric explosion models have been...
Astrophysical thermonuclear explosions typically arise from interactions in binary star systems. Their predicted observational characteristics span a wide range in parameter space and include Type Ia supernovae, as well as other classes of transient events. Understanding and interpreting the rich set of new data expected from upcoming transient searches requires advances in modelling the...
The Compton Spectrometer and Imager (COSI) is a NASA Small Explorer (SMEX) satellite mission with a planned launch in 2027. COSI operates in the $0.2-5\,\mathrm{MeV}$ gamma-ray bandpass and obtains coverage of the entire sky every day. COSI provides imaging, spectroscopy, and polarimetry of astrophysical sources, and its germanium detectors have excellent energy resolution for emission line...
The German Center for Astrophysics aims to generate knowledge and advance innovations in order to continue to position Germany at the forefront of astrophysics. It relies on broad international cooperation and strives to secure technological sovereignty through the development of new technologies and the transfer of knowledge. A particular focus is on promoting environmentally friendly...
Heavy ion storage rings have been used for nuclear astrophysics measurements for decades, and have proven themselves powerful tools for exotic mass measurements.
Recent advances in ring operation and beam intensities made measurement of nuclear reactions at rings possible. In particular, pioneering measurements were carried out at the ESR at GSI (Germany) investigating the astrophysical...
The abundances of the light elements can be spectroscopically determined by observing the low-metallicity stars. Usually, those measurements are in agreement with the Big Bang Nucleosynthesis predictions. Particularly, the Li-7 measured abundance is 3-4 times lower than expected, discrepancy known as the “cosmological Li problem”. The reaction $^3$H(α,γ)$^7$Li contributes to the production...
The $^{3}$He($\alpha,\gamma$)$^{7}$Be reaction plays a significant role in Big Bang nucleosynthesis, as well as in stellar hydrogen burning. It affects the nucleosynthesis of primordial $^{7}$Li, as well as the theoretical prediction of solar $^{7}$Be and $^{8}$B neutrino fluxes.
A measurement of its $\gamma$-ray angular distribution was performed using the 5$\,$MV Pelletron accelerator at...
Meteorites, also known as the poor scientists' space probe, are valuable samples to study the solar nebula and its constituents. Certain primitive meteorites captured the composition of the solar system and have not been altered in the 4.5 billion years since its formation. These rocks also carry nucleosynthetic anomalies that allow us to deduce stellar processes in the solar neighborhood...
The chemical enrichment history of the elements observed in the Sun and in other stars is providing crucial information about the formation and the chemical evolution of the Milky Way. The production of specific elemental ratios and isotopes can be used to constrain different uncertainties affecting galactic chemical evolution (GCE) simulations. Theoretical stellar yields are one of the major...
Studying the galactic chemical evolution with short lived radioisotopes (SLRs) has a significant advantage over using stable elements: Due to their radioactive decay, SLRs carry additional timing information on astrophysical nucleosynthesis sites.
We can use meteoritic abundance data in conjunction with a chemical evolution model to constrain the physical conditions in the last rapid...
60-Fe found in the Earth crust points to one or several core-collapse supernovae within 100-150 pc of Earth 1.5-2.5 Myr ago, probably from the young OB-associations in Scorpius, Centaurus, and Lupus.
We search for neutron stars formed in those supernovae: (i) We trace back the motion of all young neutron stars and runaway stars (whose former common multiple star system was disrupted by the...
Using a consistent statistical approach through the Backward-Forward Monte-Carlo method, we investigate both the parameter (statistic) and model (systematic) uncertainties associated with theoretical nuclear reaction rates of relevance during the i-process, and with theoretical nuclear masses of relevance during the r-process.
- For the i-process, we explore the impact on the i-process...
In 2017, a multimessenger era started with the first gravitational wave detection from the merger of two neutron stars (GW170817) and the rich electromagnetic follow-up. The most exciting electromagnetic counterpart was the kilonova. The neutron-rich material ejected during the neutron star merger undergoes an r-process that produces heavy elements and a kilonova. Moreover, observations of...
Heavy elements like gold and uranium are produced via the rapid neutron-capture (r-)process. This process only occurs in rare explosive events in the Universe, like supernovae and neutron star mergers, making it highly challenging for astronomers to gather direct observations of the element creation. Likewise, it is difficult for nuclear physicists to recreate and study the nuclear process in...
The astrophysical rapid-neutron capture process (r-process) of explosive nucleosynthesis is responsible for the formation of half of the heavy nuclei above Fe. Actinides are produced towards the end of this process, when the neutron flux is expected to be minimal, and it is supported also by fission processes. Given that the r-process path runs far away from the accessible species, in this...
The ${}^{140}$Ce(n,$\gamma$)${}^{141}$Ce is recognized as an important reaction in the flow of neutron-capture nucleosynthesis due to the neutron-magic character of ${}^{140}$Ce and a corresponding small neutron capture cross section. We present here [1] measurements of the neutron-capture Maxwellian-averaged cross section (MACS) of stable cerium isotopes performed by activation in the...
About half of the heavy elements in nature are created at the end of core helium burning in massive stars (weak $s$-process) and during the AGB phase of low-mass stars (main $s$-process). These astrophysical environments have been identified as $s$-process sites because reactions are available that produce neutrons on an appropriate time scale and quantity. The...
$^{26}$Al and $^{60}$Fe are two short-lived radioactive nuclei that can be used as tracers of the star formation. In the next years, COSI, the new $\gamma$-ray instrument by NASA will be launched and will provide us with a new insight of the distribution of these two elements in the Milky Way. In view of these new upcoming measurements, by means of a detailed 2D chemical evolution model I...
Cross-sections for neutron-induced reactions with molybdenum is relevant in various scientific fields ranging from nuclear astrophysics to nuclear technologies. In addition to its astrophysical role, molybdenum isotopes can be found in fission power plants as fission products and the use of this material is under study for future improved reactors. Molybdenum is found in pre-solar silicon...
To interpret stellar spectra 1D hydrostatic model atmospheres are most often used as a compromise between accuracy and computational cost. However, such models do not treat convection accurately and rely on approximating it with varying degrees of success. We present a new grid of 3D hydrodynamic CO5BOLD model atmospheres and use it with 3D non-equilibrium radiative transfer code MULTI3D to...
Due to the Coulomb barrier or the low-intensities of radioactive ion beams (or both!), indirect approaches to determining thermonuclear reaction rates are vital. There are many different tools, ranging from improving spectroscopy of nuclei to constrain resonance properties using charged-particle or $\gamma$-ray spectroscopy to identify resonance states and determine their spins and parities,...
ELISSA is a 4π silicon strip detector array implemented at the ELI-NP facility for measurements of photodissociation reactions using high-brilliance, quasi-monoenergetic gamma beams. The array consists of three rings of 35 single-sided X3 detectors and two end-caps made up of eight double-sided QQQ3 detectors. However, multiple configurations are possible with the YY1, MMM, and QQQ3 detectors...
Obtaining reliable cross sections for neutron-induced reactions on unstable nuclei nuclei is crucial to our understanding of the stellar nucleosynthesis of heavy elements. However, the measurement of these cross sections is very complicated, or even impossible, due to the radioactivity of the targets involved. Our aim is to circumvent this problem by using the surrogate-reaction method in...
Live radionuclides that were synthesised and ejected by stellar explosions, dispersed in the interstellar medium and subsequently deposited on Earth provide key insights about the astrophysical history of the solar neighbourhood and heavy element nucleosynthesis. The influx of supernova-produced $^{60}$Fe (t$_{1/2}$$\,$=$\,$2.6$\,$Myr) about 2.5$\,$Myr ago was reported several times within the...
Accounting for out-of-NSE (nuclear statistical equilibrium) r-process nucleosynthesis is one of the most sought-after goals in the (numerical) modelling of binary neutron star (BNS) mergers. While post-processing analysis via full nuclear networks is a reliable technique, the computational and storage costs prevent such calculations to be directly coupled to hydrodynamics codes, thus...
We have developed a compact detector system that utilizes an active-target TPC (Time Projection Chamber) to measure the $^{12}$C$(\alpha,\gamma)^{16}$O reaction. This system includes a 3-T superconducting magnet, a low-pressure He-gas TPC, and a LaBr$_3$(Ce) detector array. The proposed experiment, called COREA (Carbon Oxygen Reaction Experiment with Active-target TPC) experiment, will take...
Masterclasses are one-day outreach events for high school students, introducing them to topics of current research. Within the framework of the EU project ChETEC-INFRA, Masterclasses on Nuclear Astrophysics have been developed. This interdisciplinary field of science provides a new didactic perspective on nuclear and astrophysical processes by addressing the link between these two subjects....
The lowest metallicity stars that still exist today represent a window into the early Universe. Studying these stars gives us a local avenue to guide our understanding of star formation and supernova feedback in the early Universe, the early build-up of galaxies like our Milky Way, and the epoch of reionization.
In this talk I will review how we have become very efficient at finding these...
The recent multimessenger detections of signals from neutron star binaries has opened a new era also for the study of high density physics. With interior densities that can exceed those of an atomic nucleus, and low temperatures (at least in mature systems) compared to the Fermi temperatures of the constituents, neutron stars allow to probe very different and complementary regimes of the QCD...
The majority of elements beyond the Fe peak are produced by neutron capture processes which can be rapid (r-process) or slow (s-process) with respect to the $\beta$-decay in nuclei. Understanding which are the astrophysical formation sites of these two processes has become one of the major challenges in chemical evolution. In particular, the r-process sites are still under debate, with...
Massive stars play a crucial role in shaping the chemical composition of galaxies, enriching the interstellar medium with both light and heavy elements previously synthetized in the star through nuclear reactions. Recent advancements in stellar modelling have highlighted the beneficial effects of rotation in massive stars, enhancing the nucleosynthesis of certain elements, especially at low...
Massive stars play an important role in the synthesis of new elements in the Universe. To understand the nucleosynthetic wind-yields of such stars, there are three key-ingredients; the nuclear reaction-rates, internal mixing processes, and the stellar winds. We focus on the effects of interior mixing processes. Up to now, the calculations of stellar yields have relied on stellar evolution...
Galactic chemical evolution calculations provide invaluable feedback between abundance surveys and stellar and nuclear physics models. Until recently, only yields from single stars have been available, so chemical evolution codes do not have the capability to build a mixed population of binary and single stars. This is a serious limitation, as most stars – particularly the most massive – form...
Atomic cascades are ubiquitous in nature and have therefore been explored within many different scenarios, from atoic precision measurements to the modeling of astrophysical spectra, and up to the radiation transport in neutron-star mergers. We here introduce and discuss a classification of atomic cascades and demonstrate how they can be modeled efficiently [1,2].
In practice, however, most...
Our knowledge about dense matter explored in the cores of neutron stars remains limited. Fortunately, the detections of gravitational waves emitted from the merger of neutron stars and the corresponding electromagnetic signals provide a new way of studying supranuclear-dense material. Making use of the strength of multi-messenger astronomy, one can combine the information obtained from...
We present a new nucleosynthesis process that may take place on neutron-rich ejecta experiencing an intensive neutrino flux. The nucleosynthesis proceeds similarly to the standard $r$-process, a sequence of neutron-captures and beta-decays, however with charged-current neutrino absorption reactions on nuclei operating much faster than beta-decays. Once neutron capture reactions freeze-out the...
Neutron-capture processes made most of the abundances of heavy elements in the Solar System, however they cannot produce a number of rare neutron deficient stable isotopes (p-nuclei) lying on the left side of the valley of stability. The $\gamma$-process is recognised and generally accepted as a feasible process for the synthesis of p-nuclei in core-collapse supernovae. However this scenario...
In high energy astrophysical processes involving compact objects, such as core-collapse supernovae or binary neutron star mergers, neutrinos are likely to play an important role in the synthesis of nuclides. Neutrinos in these environments can experience collective flavor oscillations driven by neutrino-neutrino coherent forward scattering. Recently, there has been interest in exploring...
Experimental data collected in the last two decades give a clear indication that the low-energy alpha-nucleus optical potential ($\alpha$-OMP) is a crucial and not sufficiently known nuclear physics parameter in the modeling of the $\gamma$-process of heavy element nucleosynthesis. A new $\alpha$-OMP called Atomki-V2 has been developed for low energy nuclear astrophysics purposes [1]. This...
The discovery of a slowly inspiralling binary system of two neutron stars by Hulse and Taylor in 1974 made clear that the final fate of such a system would be a very violent collision between the compact stars and that -at the very least- "something interesting" would happen. Based on indirect and mostly theoretical arguments, such collisions where connected to gamma-ray bursts and also to the...
Understanding the origin of the elements, particularly elements heavier than iron, is consistently identified as a major research challenge in nuclear physics. Meeting this challenge demands new approaches to overcome extreme technical difficulties posed by reaction studies, especially those that necessitate the use radioactive ion beams. In this talk, I will present the recent progress of...
Nuclear physics plays an important role for many astrophysics applications. Nucleosynthesis simulations of heavy elements, for example, require nuclear inputs across the whole nuclear chart, far beyond the region where experimental data is available. Likewise, the description of the extremely dense neutron-rich matter in neutron stars (NS) is a challenge for nuclear physics and...
I'll present the results from a self-consistent 2-dimensional (ray-by-ray) radiation-hydrodynamic simulation of BNSM ejecta with an online nuclear network (NN) up to the days timescale. An initial numerical-relativity ejecta profile composed of the dynamical component, spiral-wave and disk winds is evolved including detailed $r$-process reactions and nuclear heating effects. A simple model for...
Since the first direct detection of gravitational waves in 2015, we have gained an entirely new observation window to the universe. The sensitivity of these interferometers is so incredible that the quantum effects of the laser light have become limiting. Ultra-precisely stabilised lasers do not suffice; non-classical light is already routinely employed in the current generation of...
Neutron star mergers lead to the ejection of multiple outflow components. Many existing neutron-star merger models cover only the first tens of milliseconds after the merger and can therefore only describe the early, dynamical ejecta. However, further matter ejection can take place during several seconds of evolution of the merger remnant. In this talk I will present our recent study [1]...
The detection of the kilonova AT2017gfo has provided us with a wealth of observations. However, to interpret these observations to obtain information about the underlying merger ejecta, including r-process nucleosynthesis, we are reliant on kilonova modelling. The majority of binary neutron star ejecta models considered when simulating kilonovae have been in 1D, or even idealised toy models,...
Type-I X-ray bursts are interpreted as thermonuclear runaways in the atmospheres of accreting neutron stars in close binary systems. These astronomical events exhibit brief, recurrent bursts of intense X-ray emission and represent some of the most frequent and violent stellar explosions to occur in our Galaxy. Recently, space-borne satellites such as the Rossi X-ray Timing Explorer (RXTE) and...
The $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne reaction is a key breakout route from the hot CNO cycle in explosive environments such as type I X-ray bursts. Determining an accurate cross section for the relevant resonant states is critical for a better understanding of the X-ray burst energy production and light-curves, and of the subsequent nucleosynthesis through the $\alpha$p- and...
The ${}^{16}$O(p,$\alpha$)${}^{13}$N reaction plays a key role in controlling the Ca/Si and Ca/S ratios synthesized during $\alpha$-rich oxygen burning in Type Ia supernovae (SNIa). This reaction feeds the $\alpha$-rich burning branch by converting ${}^{16}$O into ${}^{12}$C via the chain of ${}^{16}$O(p,$\alpha$)${}^{13}$N($\gamma$,p)${}^{12}$C. Moreover, the ${}^{16}$O(p,$\alpha$)${}^{13}$N...
In this presentation, the carbon-enriched metal-poor (CEMP) stars will be briefly reviewed. Recent progress in determining the stellar parameters, on the challenges to get benchmark stars within this category, as well as on nucleosynthetic processes that shape the composition of CEMP stars, will be reviewed. CEMP stars exhibit a rich diversity, with at least four distinct types identified. The...
The ${}^{12,13}\mathrm{C}(\mathrm{p},\gamma){}^{13,14}\mathrm{N}$ are the first reactions of the CNO cycle, active in both hydrostatic and explosive hydrogen burning. They contributes to the ${}^{12}\mathrm{C}$/${}^{13}\mathrm{C}$ isotopic ratio, observed in stellar atmosphere in meteoritic grains and in the interstellar medium. The ${}^{12}\mathrm{C}$/${}^{13}\mathrm{C}$ is a useful tool to...
Fusion reactions involving carbon and oxygen are crucial for the understanding of massive stars and of the nucleosynthesis. Besides $^{12}$C+$^{12}$C, measurements of neighbour light systems as $^{12}$C+$^{16}$O and $^{16}$O+$^{16}$O are scarce although relevant for the modelling of late carbon burning, oxygen burning in massive stars as well as explosive carbon burning of Type Ia...
The CNO cycle is the main energy production mechanism in stars heavier than our Sun, defining both their evolution and lifespan. The solar $\nu$-flux from the CNO cycle has been recently measured by the Borexino collaboration and it could provide an independent estimate of the solar metallicity, i.e.\ the CN abundance in the core of the sun.
The equilibrium of the CNO cycle is ruled by the...
The triple-alpha process is one of the most fundamental processes in stellar nucleosynthesis, and in particular, the stellar production of carbon. This process entails the fusion of three helium nuclei to form an intermediate state in $^{12}$C. This intermediate state can decay back into its three constituent alpha particles or radiatively decay to form stable $^{12}$C. At temperatures between...
We present a newly developed jet and extended windowless gas target system, tailored to meet the precision measurement demands of modern nuclear astrophysics. Our system can be operated either in jet or extended modes without necessitating modifications in pumping power. Real-time monitoring of a jet, facilitated by laser interferometry techniques, ensures control of target parameters during...
To understand and model element synthesis and energy budget in stars a large number of nuclear reaction cross sections must be known. For explosive stellar scenarios, like supernovae or x-ray bursts, this heavily involves nuclei beyond stability. However, due to the challenges inherent to related experiments, the lack of available experimental data in this domain is severe.
A new method for...
Classical novae are stellar thermonuclear explosions involving a white dwarf accreting material from a companion star. Early in the Galactic history, these explosions proceeded differently, mainly due to the accretion of sub-solar metallicity material onto the white dwarf. It has been proposed that these primordial nova explosions produce a different abundance pattern compared to their...
$^{22}$Na (T$_{1/2}$ = 2.6 y) is of high interest for space-based γ-ray astronomy because its direct observation could constrain classical nova models. Although the characteristic 1275 keV β-delayed γ decay radiation has not been observed yet, future γ-ray telescopes may detect the decay with high sensitivity. To link these observations with nova model predictions, nuclear data are needed. The...
The nucleosynthesis process involving neutron captures during stellar helium burning, known as the s-process, contributes to roughly half of the elements heavier than iron. As for Asymptotic Giant Branch (AGB) stars, they are major producers of nuclei from Sr to Pb. Despite significant theoretical progress in recent decades, uncertainties persist in AGB models, notably regarding the mechanism...
With the recent large-scale surveys such as APOGEE, GALAH, LAMOST, among others, our knowledge about stellar nucleosynthesis, as well as the chemical evolution and composition of the Milky Way, has been growing quickly. However, surveys have a trade-off between data volume and data quality, to allow probing the chemistry of the Galaxy as a whole. That results in some potentially interesting...
We present evidence that the heavy-element abundances in maybe most carbon-enhanced metal-poor stars point to i-process nucleosynthesis, at neutron densities intermediate between those of the s- and r-processes. The i process may occur in a helium convective zone that entrains hydrogen from an adjacent H-rich envelope, for example in rapidly-accreting white dwarfs, like those considered to...
