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model calculations within the framework of the so-called γ process show an underproduction of the p nucleus with the highest isotopic abundace 92mo. this discrepancy can be narrowed by taking into account the alternative production site of a type ia supernova explosion. here, the nucleus 92mo can be produced by a seque... | p-process nucleosynthesis via proton-capture reactions in thermonuclear supernovae explosions |
background: nucleosynthesis of mid-mass elements is thought to occur under hot and explosive astrophysical conditions. radiative α capture on 34s has been shown to impact nucleosynthesis in several such conditions, including core and shell oxygen burning, explosive oxygen burning, and type ia supernovae. purpose: broad... | direct measurement of resonance strengths in 34s(α ,γ )38ar at astrophysically relevant energies using the dragon recoil separator |
electron-capture and β-decay rates in stellar environments are evaluated with the use of new shell-model hamiltonians for sd-shell and pf-shell nuclei as well as for nuclei belonging to the island of inversion. important role of the nuclear weak rates on the final evolution of stellar degenerate cores is presented. the... | roles of nuclear weak rates on the evolution of degenerate cores in stars |
shell model studies have contributed in recent years significantly to improve nuclear input required in simulations of the dynamics of astrophysical objects and their associated nucleosynthesis. this manuscript highlights a few examples like electron capture rates of importance for the evolution of core-collapse supern... | shell model studies for nuclear astrophysics |
stars more massive than about 8-10 solar masses evolve differently from their lower-mass counterparts: nuclear energy liberation is possible at higher temperatures and densities, due to gravitational contraction caused by such high masses, until forming an iron core that ends this stellar evolution. the star collapses ... | massive stars and their supernovae |
binary neutron star mergers (nsms) are expected to be main production sites of r-process elements. their ejecta are extremely neutron-rich (ye<0.1), and the r-process path proceeds along the neutron drip line and enters the region of fissile nuclei. in this situation, although superheavy nuclei may be synthesized an... | impact of nuclear fission on r-process nucleosynthesis and origin of solar r-process elements |
we have recently commissioned a novel infrared (0:9-1:7 μm) integral field spectrograph (ifs) called the wide integral field infrared spectrograph (wifis). wifis is a unique instrument that offers a very large field-of-view (5000 x 2000) on the 2.3-meter bok telescope at kitt peak, usa for seeing-limited observations a... | the wide integral field infrared spectrograph: commissioning results and on-sky performance |
we report c, n, al-mg, si, and s isotope data of 22 presolar sic grains of type ab, which are discussed in the context of two supernova models. | isotopic signatures of supernova nucleosynthesis in presolar sic grains of type ab with light nitrogen |
based on the shell-model, and the linear response theory, we discuss the influence of strong electron screening (ses) on the γ -ray heating rates (grhr) by beta decay for several typical iron group nuclei. we calculate the screening potential caused by the relativistically degenerate electron. we also investigate the e... | strongly screening γ -ray heating rates by β- decay of 59co, 55co, 56ni, and 56fe in presupernova |
the chemical evolution of the universe is governed by the yields from stars, which in turn is determined primarily by the initial stellar mass. stars less massive than about 10 solar masses experience recurrent mixing events on the giant branches that can significantly change the surface composition of the envelope. ob... | evolution and nucleosynthesis of low and intermediate-mass stars |
globular clusters are now known to harbour helium-rich stellar populations. while the stars we see today are all of low mass, there were once stars of all mass ranges with helium mass fractions up to y ≈ 0.40. it has also been suggested that the younger stellar component of the galactic bulge is both metal-rich and hel... | the effect of enhanced helium abundances on the agb-supernove mass transition |
measurements of the radioactive 244pu abundances can break the degeneracy between high-rate/low-yield and low-rate/high-yield scenarios for the production of heavy r-process elements. the first corresponds to production by core collapse supernovae (cc-sne) while the latter corresponds to production by e.g., neutron sta... | short-lived 244pu points to neutron star binary mergers as sites for r-process nucleosynthesis |
chempy models galactic chemical evolution (gce); it is a parametrized open one-zone model within a bayesian framework. a chempy model is specified by a set of 5-10 parameters that describe the effective galaxy evolution along with the stellar and star-formation physics: e.g. the star-formation history (sfh), the feedba... | chempy: a flexible chemical evolution model for abundance fitting |
the 22ne(p,γ)23na reaction is involved in the nena cycle of hydrogen burning. this cycle plays an important role for nucleosynthesis in the red giant branch and asymptotic giant branch phases of stellar evolution, as well as in classical novae and type ia supernovae explosions. the 22ne(p,γ)23na reaction rate is highly... | towards a study of 22ne(pγ)23na at luna |
stars in low-mass dwarf galaxies show a larger range in their chemical properties than those in the milky way halo. the slower star formation efficiency make dwarf galaxies ideal systems for testing nucleosynthetic yields. not only are alpha-poor stars found at lower metallicities, and a higher fraction of carbon-enhan... | chemical abundances of metal-poor stars in dwarf galaxies |
synthesis of chemical elements is investigated at conditions of magnetorotational instabilities in astrophysical plasma at supernova explosion. effects of ultra-strong nuclear magnetization are demonstrated to enhance the portion of titanium product. the relation to an excess of 44ti revealed from the integral mission ... | nucleosynthesis at magnetorotational supernova explosion and galactic chemical evolution |
observations of supernovae and their remnants reveal highly aspherical distributions of the newly-formed elements that are the dying stars' contributions to the interstellar medium. modern simulations of the supernova's neutrino-powered central engine reveal that these inhomogeneities originate in the first seconds of ... | the multidimensional character of nucleosynthesis in core-collapse supernovae |
we study the impact of neutrino-nucleus reactions on the nucleosynthesis in shock-heated supernova ejecta. nucleosynthesis calculations with an extensive set of neutrino-induced reactions are performed, including updated insights into expected neutrino properties in a supernova environment. sensitivities and mechanisms... | neutrino induced nucleosynthesis of radioactive nuclei in core-collapse supernovae |
we perform detailed nucleosynthesis calculations for two long-term, 2d simulations of core-collapse supernovae. we find that elements are produced up to ru (z = 44) and observe abundance patterns that are characteristic of a νp-process. one important characteristic of the long-term simulation is that there is still acc... | nucleosynthesis in 2d core-collapse supernova long-term simulations of 11.2 and 17.0 m ⊙progenitors |
we present the results of an analysis of the archival xmm-newton epic data (203ks for pn and 556/574ks for mos1/mos2) and the chandra x-ray observatory acis data (89ks) of the brightest x-ray supernova remnant (snr) in the large magellanic cloud (lmc) n132d. n132d has been classified as an ``o-rich'' remnant based on t... | an archival x-ray study of the large magellanic cloud supernova remnant n132d |
some of the most energetic explosions in the universe are the core-collapse supernovae (ccsne) that arise from the death of massive stars. they herald the birth of neutron stars and black holes, are prodigious emitters of neutrinos and gravitational waves, influence galactic hydrodynamics, trigger further star formatio... | progenitor masses for every nearby historic core-collapse supernova |
we have observed the oxygen-rich snr 1e 0102.2-7219 with the integral field spectrograph wifes at siding spring observatory and discovered sulfur-rich ejecta for the first time. follow-up deep ddt observations with muse on the vlt (8100 s on source) reaching down to a noise level of ~5 × 10-20ergs-1cm-2å-1spaxel-1 have... | muse integral field observations of the oxygen-rich snr 1e 0102.2-7219 |
the 20ne(α,p)23na reaction rate is important in determining the final abundances of various nuclei produced in type ia supernovae. previously, the ground state cross section was calculated from time reversal reaction experiments using detailed balance. the reaction rates extracted from these studies do not consider con... | 20ne(α,p)23na studied to constrain type ia nucleosynthesis |
highlights from the nif discovery science program will be presented. examples include nuclear reactions relevant to stellar nucleosynthesis; equations of state at high pressures relevant to planetary interiors and white dwarf envelopes; rayleigh-taylor instabilities relevant to supernovae and supernova remnant evolutio... | exploring the universe through discovery science on the national ignition facility (nif) |
direct measurements of radiative proton and alpha capture reactions are crucial for understanding nucleosynthesis in a variety of astrophysical environments, including classical novae, supernovae, x-ray bursts, and quiescent stellar burning. often the most important reactions have very low cross sections or involve uns... | direct measurements of radiative capture reactions with dragon |
first stars in the universe must have played crucial roles in the evolution of early universe, yet their nature has not been well-understood. i will present possible theoretical models of first stars, i.e., their evolution with mass accretion, explosions as first supernovae, and explosive nucleosynthesis. i will show h... | first stars: their supernova explosions and connections to extremely iron-poor stars |
rcw 103 is a galactic supernova remnant (snr) with a bilateral morphology and hosting the peculiar central compact object (cco) 1e 161348-5055. we present a chandra and xmm-newton imaging and spectroscopic study of rcw 103 with the goal to determine the intrinsic properties of the snr including the explosion energy, am... | an x-ray imaging and spectroscopic study of the supernova remnant rcw 103 using chandra and xmm-newton |
spectroscopy of x-ray and gamma-ray lines is one of the most powerful tools of high-energy astrophysics. in this paper we give an overview of the scientific potential of a high-energy x-ray (1-160kev) imaging telescope using an array of transition-edge sensor microcalorimeters that achieves a spectral resolution (10's ... | high-resolution x-ray and gamma-ray spectroscopy with transition-edge sensors |
classical novae are thermonuclear explosions that take place in the h-rich envelopes of accreting white dwarfs in stellar binary systems. the material piles up under degenerate conditions, driving a thermonuclear runaway. the energy released by the suite of nuclear processes operating at the envelope heats the material... | classical novae, recurrent novae, and the pathway towards type ia supernovae |
the production of the p-nuclei is one of the unsolved puzzles in nuclear astrophysics. a possible mechanism is the nucleosynthesis in the neutrino-driven winds of core-collapse supernovae (νp-process), but it carries uncertainties, mostly in the supernova dynamics and the nuclear physics input. the pp-chain breakout re... | study of the 7be(α,γ)11c reaction with dragon for vp-process nucleosynthesis |
the fast-expanding neutron rich neutrino-driven winds in the core-collapse supernovae is one of the most favorable scenario for the nucleosynthesis of the z = 38-47 elements. charge particle reactions, especially (α,xn) on heavy nuclei of the range 80 < a < 90 create seeds for the weak r-process populating abunda... | cross-section measurement of the 85br(α,xn) and it's implication in the weak r-process. |
phosphorus is a key element for life on earth and is thought to be created in different nucleosynthesis channels, however few precise stellar p abundances exist. the 150 known p abundances do not match chemical evolution models and the most significant sites of p nucleosynthesis are unclear. to understand the chemical ... | the galactic chemical evolution of phosphorus: a survey of 163 stars with the habitable-zone planet finder instrument |
radioactive isotopes produced in core-collapse supernovae (ccsne) provide useful insights into the underlying processes driving the collapse mechanism and the origins of elemental abundances. here we identify the key nuclear reaction rates to the nucleosynthesis of observable radioactive isotopes in explosive silicon-b... | reaction rate sensitivity of the production of γ-ray emitting isotopes in core-collapse supernova |
files table1.dat to table4.dat list the nucleosynthesis yields of all models. all yieldes are given in solar masses. the isotope name is given in the first column. this is followed by the nucleosynthetic yields originating from the shell and core detonation for each model. file table1.dat gives the stable nuclides, rad... | vizier online data catalog: impact of core and shell masses on sne ia (gronow+, 2021) |
the three most iron-poor stars known until now are also known to have peculiar enhancements of intermediate mass elements. under the assumption that these iron-deficient stars reveal the nucleosynthesis result of pop iii stars, we show that a weak supernova model successfully reproduces the observed abundance patterns.... | stellar yields of rotating first stars: yields of weak supernovae and abundances of carbon-enhanced hyper metal poor stars |
we have developed a new approach to the mixing length theory of convection for use in spherically symmetric core-collapse supernova simulations. this approach is based on the results of multidimensional simulations with the goal of more accurately reproducing successful explosions, the composition and thermodynamic var... | a new approach to mixing length theory of convection for spherically symmetric supernova simulations |
neutrino flavor transformations occurring in neutron star mergers and core collapse supernovae may significantly modify the amount of electron flavor content and thus the nucleosynthesis outcomes of these events. especially important to determining the neutrino flavor in such events is the fast-growing neutrino flavor ... | neutrino flavor transformations with emu: a new particle-in-cell code for quantum kinetics |
the knowledge of beta-decay transitional probabilities and gamow-teller (gt) strength functions from highly excited states of nuclides is of particular importance for applications to astrophysical network calculations of nucleosynthesis in explosive stellar events. these quantities are challenging to achieve from measu... | validity of brink-axel hypothesis for calculations of allowed stellar weak rates of heavy nuclei |
i will first review the various channels that can lead to the formation of thorne-zytkow objects (tzos) and discuss the physical uncertainties and recent theoretical developments regarding the formation process, the modeling of tzos themselves and their expected lifetimes. i will then outline nucleosynthesis signatures... | the formation and evolution of thorne-zytkow objects |
the mass 80 peak of the r-process abundance pattern is believed to be the product of multiple possible astrophysical environments. among these is a possible weak r-process that could occur in hot (~ 1 gk) environments such as core-collapse supernovae. neutron-capture rates on se isotopes have been identified by surman ... | 82 se(d,pγ) with goddess for weak r-process nucleosynthesis |
the origin of the rapid neutron-capture process is a major question in astrophysics. the key to this question is the chemical abundance patterns of very metal-poor stars (vmp), which are believed to reflect the nucleosynthesis yields of single event. recent observations of vmp indicate that there are at least two compo... | abundance of weak r-process elements of metal-poor stars ∼universality or diversity?∼ |
the weak processes are a key to understand the nucleosynthesis of heavy elements in the universe. in this work we have studied weak processes such as β-decay and neutrino capture that are very important for the r-process. this process takes place in a region between neutron drip and β-stability line. for nuclei far fro... | weak process for iron isotopes chain used as seed for heavy elements nucleosynthesis |
cosmological chemodynamical simulations are nowadays among the best tools to study how chemical elements are produced within galaxies, to reconstruct also the spatial distribution of the chemical elements as a function of time within different galaxy environments. our simulation code includes the main stellar nucleosyn... | radial elemental abundance gradients in galaxies from cosmological chemodynamical simulations |
supernovae - explosions of stars - are a central problem in astrophysics since they encapsulate the entire process of stellar evolution and nucleosynthesis. rayleigh-taylor (rt) and richtmyer-meshkov (rm) instabilities, developing during the supernova blast, lead to intense mixing of the star's materials and couple ast... | fluid dynamics of supernova remnants |
the discovery of three hypervelocity white dwarfs (wds) in the the gaia dr2 catalog provided observational evidence of the ex-companions of sub-chandrasekhar (sub-mch) wds which underwent type ia supernovae (sne ia) explosions in a variant of the double-degenerate scenario. in this talk, i will present recent 3d hydrod... | 3d hydrodynamical simulations of the dynamically driven double-degenerate double-detonation scenario of type ia supernovae |
the 3-d structure of metal-rich ejecta in supernova remnants (snrs) imposes critical information to study the sn explosion asymmetry, explosive nucleosynthesis, and the snr dynamics. a straightforward way to reveal the 3-d distribution of the reverse-shocked ejecta in snrs is to measure doppler-shifted radial velocitie... | a chandra hetgs observation of kepler's supernova remnant |
because of their immense power, gamma-ray bursts (grbs) have the potential to be detected, and hence, probe stellar properties and star formation out to high redshifts. to be used as probes, we must understand the evolution of grbs with metallicity and redshift. we present theoretical results based on the collapsar grb... | gamma-ray burst evolution with redshift |
the 34cl(p,γ)35ar reaction is an important step in the study of the creation of heavy nuclei during the rapid proton capture nucleosynthesis (r-p process) in supernova. study of this reaction is important for reducing uncertainties in supernova model. such studies are largely dependent on being able to maximize the 34c... | study of 34mcl beam production at the national superconducting cyclotron laboratory |
the observation of γ rays from the decay of 44ti in the remnants of core-collapse supernovae (ccsne) provides crucial information regarding the nucleosynthesis occurring in these events, as 44ti production is sensitive to ccsne conditions. the final abundance of 44ti is also sensitive to specific nuclear input paramete... | 58ni(3he,t)58cu*(γ) measurements with goddess to constrain the astrophysical rate of 57ni(p,γ)58cu |
neutrinos radiate 99% of the energy and play a crucial role in the explosion mechanism and nucleosynthesis of core-collapse supernovae. the neutrino interactions in hot and dense matter is a complex problem due to bound nuclei and the strong nuclear forces. in this work we calculate the dynamic and static response of t... | impact of eos on neutrino opacities in core-collapse supernovae |
neutron-induced reactions are essential to the nucleosynthesis of the elements heavier than iron. recent studies show that key (n,p) reactions, such as the 56ni(n,p)56co and 64ge(n,p)64ga, regulate the efficiency of the so-called neutrino-p process (νp-process), which is responsible for the formation of elements betwee... | preparation of the secar system for the first (p,n) reaction measurement. |
the synthesis of galactic 26al is an interesting subject that spans from nuclear astrophysics to observational astronomy. this isotope is observed through γ-ray astronomy and is a probe into the ongoing nucleosynthesis in the galaxy as well as the frequency of core-collapse supernovae. one of the reactions of interest ... | measurement of low-lying proton resonances in 26si using the 25al(d,n)26si proton transfer reaction. |
neutron star mergers (nsms) are the first verified site of rapid neutron capture (r-process) nucleosynthesis, and could emit gamma rays from the radioactive isotopes synthesized in the neutron-rich ejecta. these mev gamma rays may provide a unique and direct probe of the nsm environment as well insight into the nature ... | mev gamma rays from fission: a distinct signature of actinide production in neutron star mergers |
the nucleosynthetic signatures of the first stars and supernovae are imprinted in the atmosphere of the long-lived, iron-poor star he1327-2326 (with [fe/h] = -5.4). comparing the abundance signatures of stars like he1327-2326 with predictions of early low-mass star formation pathways as well as low-metallicity supernov... | constraining pop iii supernova energies and the formation of the first low-mass stars with the iron-poor star he1327-2326 (with [fe/h] = -5.4) |
type ia supernovae are generally considered to be the result of the thermonuclear disruption of carbon oxygen white dwarfs. however, the exact mechanism behind the explosion remains uncertain. the pre-explosion progenitor of a white dwarf has never been observed, so all conclusions must be drawn from comparisons betwee... | investigating the effects of progenitor metallicity on observable features of chandrasekhar mass type ia supernovae and improving detonation models of sub-chandrasekhar mass type ia supernovae |
in this work i present numerical magnetohydrodynamic (mhd) simulations of the early dynamics around newly born neutrons stars using the amr flash method. when the core-collapse supernovae occurs a reverse shock is formed allowing strong accretion onto the neutron star surface (hypercritical phase). in such regime large... | on the submergence and reemergence of magnetic fields in young supernovae |
based on a new mechanism to drive spherically symmetric core-collapse supernovae, push, we perform full network nucleosynthesis calculations for different progenitors. while the 56-58ni yields match the observational data very well for certain progenitors, the ejected titanium masses in our calculations are lower than ... | explosive nucleosynthesis in core-collapse supernovae and the titanium problem |
lp 40-365 is an hypervelocity star, whose atmosphere is dominated by oxygen, neon, and magnesium, and it is sprinkled with the ashes of partial oxygen and silicon burning. its composition and remarkable kinematics suggest this star formed via the failed disruption of a near-chandrasekhar mass white dwarf in a peculiar ... | partly burnt white dwarfs from peculiar thermonuclear supernovae |
core-collapse supernovae (ccsne) are the highly energetic deaths of massive stars. they play a vital role in the synthesis and dissemination of many chemical elements. ccsn nucleosynthesis calculations have previously relied on artificial explosion methods that do not adequately capture the physics of the innermost ste... | pushing core-collapse supernovae to explosions in spherical symmetry: explodability and nucleosynthesis yields |
the evolution of neutrino flavor in dense environments such as core-collapse supernovae and binary compact object mergers constitutes an important and unsolved problem. its solution has potential implications for the dynamics and heavy-element nucleosynthesis in these environments. in this paper, we build upon recent w... | inference of neutrino flavor evolution through data assimilation and neural differential equations |
the 2021 heineman prize recognizes technical and scientific contributions to astronomical surveys, especially the sloan digital sky survey (sdss), which has been one of the most influential astronomy projects of the past half-century. we will jointly recap our experiences with the early phases of the sdss, then each ta... | asteroids to reionization: the broad reach of survey astronomy |
astrobites reports on a radio-wavelength search for heavy metals from special supernovae called collapsars. | a tale of three rs: radio, r-process, and collapsars! |
in a previously presented proof-of-principle study, we established a parameterized spherically symmetric explosion method (push) that can reproduce many features of core-collapse supernovae (ccsn). the present paper goes beyond a specific application that is able to reproduce observational properties of sn1987a and per... | vizier online data catalog: push ccsn to explosions in spherical symmetry. ii. (ebinger+, 2019) |
the dwarf galaxies in the local group are excellent laboratories for studying the creation of the elements (nucleosynthesis) and the build-up of those elements over time (chemical evolution). the galaxies' proximity permits spectroscopy of individual stars, from which detailed elemental abundances can be measured. thei... | dwarf galaxies: laboratories for nucleosynthesis and chemical evolution |
nucleosynthesis at magnetorotational supernova explosion is considered by employing arguments of nuclear statistical equilibrium. effects of ultra-strong nuclear magnetization are demonstrated to enhance the portion of titanium product. the relation to an excess of 44ti revealed from the integral mission data and galac... | nuclear magics at magnetorotational supernova explosion |
the equation of state, transport and linear response properties of hot and dense neutron-rich matter created in core-collapse supernovae and neutron star mergers directly affect the observable electromagnetic, neutrino, and gravitational wave signals as well as the possibility for r-process nucleosynthesis in the eject... | hot and dense neutron-rich matter in supernovae and neutron star mergers |
details of the core-collapse supernova (ccsn) explosion mechanism still need to be fully understood. there is an increasing number of successful examples of reproducing explosions in multidimensional hydrodynamic simulations, but subsequent studies pointed out that the growth rates of the explosion energy of these simu... | 56 ni problem in core-collapse supernova explosion |
we report the result of a high-resolution spectroscopic study on seven magnesium (mg) enhanced stars. the high mg abundances in these stars imply that they were born in an environment heavily affected by the nucleosynthesis products of massive stars. we measure abundances of 16 elements including mg and they show vario... | graces observations of mg-enhanced metal-poor stars in the milky way |
in spite of years of effort many aspects of the origin and evolution of heavy elements in nature are yet to be understood. in this talk we will summarize the current status of models for both the formation of r-process nucleosynthesis and the p-process. we describe state-of the art developments of supernova and binary ... | contribution of collapsars and hypernovae to the origin and early evolution of heavy element explosive nucleosynthesis |
galaxy clusters are known as grand reservoir of metals as their intracluster medium (icm) are gradually enriched by supernova (sn) explosions. the azimuthal and spatial distributions of these metals from cluster's centre out to the virial radius are of vital importance since they record all the information on nucleosyn... | suzaku observations of chemical enrcihment history of galaxy cluster a3112 |
the origin of the elements from roughly zinc to tin (30 < z < 50) has yet to be determined. the neutron-rich neutrino driven winds of core collapse supernovae (ccsn) are a proposed site for the nucleosynthesis of these elements. however, a significant source of uncertainty exists in elemental abundance yields fro... | development of a neutron long counter detector for (α, n) cross section measurements at ohio university |
at the end of its life, a massive star collapses into a neutron star leading to a supernovae explosion. the neutrino flux released during the collapse is so significant that the probability of a neutrino interacting with a nucleus can actually influence the nucleosynthesis. the origins of light element, especially 11b,... | reaction rate studies of 7li(a,g)11b at nu-process energies |
the propagation of uncertainties in reaction cross sections and rates of neutron-, proton-, and α-induced reactions into the final isotopic abundances obtained in nucleosynthesis models is an important issue in studies of nucleosynthesis and galactic chemical evolution. we developed a monte carlo method to allow large-... | impact of uncertainties in nuclear reaction cross sections on p nucleosynthesis in thermonuclear supernovae |
gamow-teller strengths in fp-shell nuclei obtained by a new shell-model hamiltonian, gxpf1j, are used to evaluate electron-capture rates in ni and fe isotopes etc. at stellar environments. the updated e-capture rates as well as β-decay rates are applied to study nucleosynthesis in type-ia supernova explosions, rp-proce... | electron-capture rates for exotic nuclei at stellar environments |
recently the first phosphorus abundance measurements have been reported from spectroscopic studies of galactic disk stars and have allowed for comparisons to chemical evolution models. phosphorus is thought to be primarily made through neutron capture during hydrostatic burning in massive stars and little contribution ... | exploring phosphorus nucleosynthesis with chemical abundances in disk stars and chemically peculiar giants |
in spite of many years of effort, some aspects of the origin and evolution of heavy elements in nature are yet to be understood. here, we overview the current status of models for the formation of both r-process and νp-process elements. we summarize recent state-of the art developments of supernova and binary neutron s... | the r-process and νp-process in ccsne, collapsars, hypernovae and mergers, and their effect on galactic chemical evolution |
supertiger (super trans-iron galactic element recorder) is a long-duration-balloon instrument that completed its first antarctic flight during the 2012-2013 austral summer, spending 55 days at an average float altitude of 125,000 feet, and a second flight in the 2019-2020 austral summer completing 32 days of flight at ... | galactic cosmic ray nuclei abundances from 10ne to 56ba with supertiger |
during nucleosynthesis (α,p) reactions are important in a variety of astrophysical sites, including classical novae, x-ray bursts and supernovae. direct measurements of these reaction rates are needed to reduce uncertainties and understand the nucleosynthesis in these stellar sites. sensitivity studies indicate that th... | studying 20ne(α,p)23na directly with helios |
nucleosynthesis, the origin of elements, is one of the greatest mysteries in physics. a recent particular nucleosynthesis process of interest is the charge-particle process (cpp). in the cpp, elements form by nuclear fusion reactions during supernovae. this process of nuclear fusion, (α,n), will be studied by colliding... | optimization of the efficiency of a neutron detector to measure (α, n) reaction cross-section |
a very massive star that forms a large co core of ∼60-120 m ⊙finally explodes as a pair instability supernova (pisn). because currently published data are restricted to either zero-metallicity models or explosions without hydrogen envelopes, we aim to construct a new grid of pisn calculations, which spans wide initial ... | systematic calculation of pisn explosion and nucleosynthesis |
radiative capture reactions, such as (α,γ), (p,γ) and (n,γ), are of fundamental importance to the study of nucleosynthesis of elements in stellar cores, supernovae, etc. in the laboratory, these reactions are usually measured by bombarding gas targets or very thin films with particle beams. the low density of these tar... | a single fluid bubble chamber for measuring nuclear reaction rates of astrophysical importance. |
we consider observational constraints from iron-group elemental and isotopic ratios, to compare with various models. the nucleosynthesis is sensitive to highest white-dwarf central densities. hence, nucleosynthesis yields can distinguish high-density chandrasekhar-mass models from lower-density burning models such as w... | nucleosynthesis constraints on the explosion mechanism for type ia supernovae |
the fast-expanding neutron-rich neutrino-driven winds in the core-collapse supernovae are favorable scenarios for the nucleosynthesis of the light-heavy elements. charge particle reactions, especially (α,n) create seeds for the weak r-process populating abundances of near stable isotopes for the sr-ag range, for which ... | measurements of (alpha,n) cross-sections relevant for the r-process |
neutron star mergers are confirmed sites of r-process nucleosynthesis, observationally identified by their kilonovae. in particular, the study of short gamma-ray bursts (sgrbs), which span z~0.1-2, are a promising avenue to uncover kilonovae. monitoring the temporal and color evolution of sgrb-kilonovae provides quanti... | solidifying the origin of a possible kilonova at 350 mpc |
nucleosynthesis models of core-collapse supernovae are validated by comparing radioisotope abundances predicted by models to abundances inferred from the observation of gamma rays emitted in supernovae remnants. one such radioisotope, 44ti, is especially sensitive to the reaction rate of 57ni(p,γ)58cu. to effectively v... | 58 -ni(3he,t)5cu*(γ) measurements with goddess to constrain astrophysical rate of 57ni(p,γ)5cu |
very metal-poor (vmp) stars ([fe/h] < - 2) of mass <~ 0 . 8 ,modot are thought to be the fossil records of the nucleosynthesis of the earliest generation of massive stars that were present in the early galaxy. a large fraction of vmp stars are found to be enhanced in c relative to fe ([c/fe] > 0 . 7) and are r... | rapidly rotating massive pop iii stars: a solution for high carbon enrichment in the early galaxy |
a sic sn grain identified by ion imaging has the highest 12c/13c ever found for presolar grains and provides a unique opportunity to study sn he shell matter. | new insights into supernova nucleosynthesis from a presolar sic grain with unique carbon isotopic composition |
the material used to form the cemp-no stars presents signatures of processing by the cno cycle and by he-burning from a previous stellar generation called spinstars. we compare the composition of the ejecta (wind + supernova) of a spinstar model to observed abundances of cemp-no stars. we show that observed abundances ... | clues on the first stars from cemp-no stars |
every element found in nature has a unique history, and it is only through careful examination of each element in the solar system and elsewhere in the universe that we gain an appreciation of this history. the story of germanium is only beginning to be understood. germanium has only been detected in a handful of other... | the astrophysical origins of germanium from the first stars until today |
we present a series of asymmetric supernova simulations in three dimensions, including a state-of-the-art model seeded with realistic convective asymmetries from a 3d stellar evolution model, the first supernova simulation of its kind. using comparative analysis and visualization of this set of supernova models, we exp... | dependence of simulated supernova yields on explosion morphology |
the stellar progenitor problem for type ia supernovae is widely recognized as one of the key questions in modern astrophysics. perhaps the leading theoretical challenge shared by all sne ia channels is the detonation initiation mechanism within the dense electron degenerate plasma in the white dwarf interior. the turbu... | turbulence-driven deflagration-to-detonation transition in near-chandrasekhar mass type ia supernovae |
the gas in galaxy clusters is enriched in metal, typically to about 30% of solar metallicity. however, stars a relatively rare in clusters, meaning that the amount of metal produced per star is about 3 times as much as in the milky way. we set out to determine what changes to standard star formation are needed to repro... | the imf in galaxy clusters: what is needed to account for high metal production? |
elemental abundances of metal-poor stars provide useful constraints on the modeling of r-process nucleosynthesis and its origins. continuous efforts have been made for measurements of heavy elements in a large number of field metal-poor stars in the milky way. measurements have been extended to stars in satellite dwarf... | observational constraints on the astrophysical site of the r-process |
in the transitional mass range between white dwarf formation and iron core-collapse supernovae, stars are theoretically expected to become super-asymptotic giant branch stars with a degenerate o+ne+mg core, and electron capture onto ne and mg nuclei should initiate core collapse. in this talk, i will present six indica... | the electron-capture origin of supernova 2018zd |
type ia supernovae (snia) are known to produce several elements in the iron-peak region via fusion reactions that occur in the explosion. vanadium (v) is an isotope on the low end of the iron-peak and one of the most abundant transition metals in seawater on earth. there are two stable isotopes of v on earth, 50v and 5... | nucleosynthesis of ⁵¹v in type ia supernovae |
recent theoretical work compellingly argues that a substantial fraction of type ia supernova (sne ia) events are explosions of near-chandrasekhar mass (mch) white dwarfs (wds). as much as half of the total sne ia rate is required to come from these sources in order to produce a solar abundance of 55mn. yet, numerous ob... | near-chandrasekhar-mass type ia supernovae from the double-degenerate channel |
recent observational advances have enabled high resolution mapping of ti-44 in core-collapse supernova (ccsn) remnants. comparisons between observations and 3d models provide stringent constraints on the ccsn mechanism. however, recent work has identified several uncertain nuclear reaction rates that influence ti-44 an... | sensitivity of ti-44 and ni-56 production in shock-driven nucleosynthesis to nuclear reaction rate variations and the case of 39k(p,g)40ca. |
we present a case study of several multi-dimensional smoothed particle hydrodynamics simulations with large nuclear network post-processing in which the effects of asymmetries on nucleosynthesis in supernovae are assessed. the abundances and spatial distribution of the short-lived radionuclides 26al, 41ca, and 60fe are... | a case study of nucleosynthesis in multi-dimensional supernova simulations |
the mev gamma-ray band is the only region of the electromagnetic spectrum where we can directly measure spectral lines from nuclear excitations and de-excitations. gamma-ray lines have been detected from radioactive isotopes produced in nuclear burning inside stars and supernovae, and from energetic-particle interactio... | understanding element formation in dynamic environments with mev gamma-ray spectroscopy |
dwarf galaxies are excellent laboratories of chemical evolution. many dwarf galaxies have simple star formation histories with very low average star formation rates. these conditions simplify models of chemical evolution and facilitate the identification of sites of nucleosynthesis. dwarf galaxies also host extremely m... | introduction |
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