A5085964910- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Nuclear physics research studies
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Pulsars and Gravitational Waves Research
- X-ray Spectroscopy and Fluorescence Analysis
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Quantum Chromodynamics and Particle Interactions
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Astronomical Observations and Instrumentation
- Dark Matter and Cosmic Phenomena
- Planetary Science and Exploration
Institut d'Estudis Espacials de Catalunya
2016-2025
Universitat Politècnica de Catalunya
2016-2025
University of Amsterdam
2014-2016
National Institute for Astrophysics
2016
University of North Carolina at Chapel Hill
2004-2011
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
2011
University of Pisa
2011
Institute of Space Sciences
2008-2011
Triangle Universities Nuclear Laboratory
2010-2011
Monash University
2011
Detailed nucleosynthesis in the ejecta of classical novae has been determined for a grid hydrodynamic nova models. The reported 14 evolutionary sequences, followed from onset accretion up to explosion and ejection stages, span range CO ONe white dwarf masses (0.8-1.35 M☉) mixing levels between accreted envelope underlying core (25%-75%). synthesis each isotope 1H 40Ca is discussed, along with its sensitivity model parameters. Special emphasis placed on isotopes such as 13C,15N, 17O, whose...
Infrared and ultraviolet observations of nova light curves have confirmed grain formation in their expanding shells that are ejected into the interstellar medium by a thermonuclear runaway. In this paper, we present isotopic ratios intermediate-mass elements up to silicon for ejecta CO ONe novae, based on 20 hydrodynamic models explosions. These theoretical estimates will help properly identify grains primitive meteorites. addition, equilibrium condensation calculations used predict types...
Classical novae eject significant amounts of nuclear-processed material into the interstellar medium. Among isotopes synthesized during such explosions, two radioactive nuclei deserve particular attention: 22Na and 26Al. In this paper, we investigate nuclear paths leading to 26Al production nova outbursts by means an implicit hydrodynamic code that follows course thermonuclear runaway from onset accretion up ejection stage. New evolutionary sequences ONe have been computed, using updated...
We investigate the effects of thermonuclear reaction-rate uncertainties on nova nucleosynthesis. One-zone nucleosynthesis calculations have been performed by adopting temperature-density-time profiles hottest hydrogen-burning zone (i.e., region in which most takes place). obtain our from seven different, recently published, hydrodynamic simulations covering peak temperatures range Tpeak = 0.145 to 0.418 GK. For each these profiles, we individually varied rates 175 reactions within their...
We report the discovery of five SiC grains and one graphite grain isolated from Murchison carbonaceous meteorite whose major-element isotopic compositions indicate an origin in nova explosions. The are characterized by low 12C/13C (4-9) 14N/15N (5-20) ratios, large excesses 30Si (30Si/28Si ratios range to 2.1 times solar), high 26Al/27Al ratios. These signatures theoretically predicted for ejecta ONe novae cannot be matched any other stellar sources. Previous studies presolar primitive...
Type I X-ray bursts are violent stellar events that take place on the H/He-rich envelopes of accreting neutron stars. We have investigated role played by uncertainties in nuclear processes nucleosynthesis accompanying these explosive phenomena. Two different approaches been adopted, framework post-processing calculations. In first one, rates varied individually within uncertainties. Ten models, covering characteristic parameter space for events, considered. The second, somewhat complementary...
Classical novae are fascinating stellar explosions at the crossroads of astrophysics, nuclear physics, and cosmochemistry. In this review, we briefly summarize 30 years nucleosynthesis studies, with special emphasis on recent advances in nova theory (including multidimensional models) as well experimental efforts to reduce uncertainties affecting critical reaction rates. Among topics that covered, outline interplay between outbursts galactic chemical abundances, synthesis radioactive nuclei...
ABSTRACT The Andromeda Galaxy recurrent nova M31N 2008-12a had been observed in eruption 10 times, including yearly eruptions from 2008 to 2014. With a measured recurrence period of <?CDATA ${P}_{\mathrm{rec}}=351\pm 13$?> days (we believe the true value be half this) and white dwarf very close Chandrasekhar limit, has become leading pre-explosion supernova type Ia progenitor candidate. Following multi-wavelength follow-up observations 2013 2014 eruptions, we initiated campaign ensure early...
Extreme excesses of $^{13}C$ ($^{12}C$/$^{13}C$<10) and $^{15}N$ ($^{14}N$/$^{15}N$<20) in rare presolar SiC grains have been considered diagnostic an origin classical novae, though core collapse supernovae (CCSNe) has also proposed. We report C, N, Si isotope data for 14 submicron- to micron-sized $^{13}C$- $^{15}N$-enriched ($^{12}C$/$^{13}C$<16 $^{14}N$/$^{15}N$<~100) from Murchison, their correlated Mg-Al, S, Ca-Ti when available. These are enriched $^{15}N$, but with quite diverse...
Classical novae are important producers of radioactive nuclei, such as 7Be, 13N, 18F, 22Na and 26Al. The disintegration these nuclei produces positrons (except for 7Be) that through annihilation with electrons produce photons energies 511 keV below. Furthermore, 7Be decay producing 478 1275 keV, respectively, well in the γ-ray domain. Therefore, potential sources emission. We have developed two codes order to analyse carefully emission individual classical novae: a hydrodynamical one, which...
Type I X-ray bursts are thermonuclear stellar explosions driven by charged-particle reactions. In the regime for combined H/He-ignition, main nuclear flow is dominated rp-process (rapid proton-captures and beta+ decays), 3 alpha-reaction, alpha-p-process (a suite of (alpha,p) (p,gamma) reactions). The expected to proceed away from valley stability, eventually reaching proton drip-line beyond A = 38. Detailed analysis relevant reactions along path has only been scarcely addressed, mainly in...
Half a century has passed since the foundation of nuclear astrophysics. Since then, this discipline reached its maturity. Today, astrophysics constitutes multidisciplinary crucible knowledge that combines achievements in theoretical astrophysics, observational astronomy, cosmochemistry and physics. New tools developments have revolutionized our understanding origin elements: supercomputers provided astrophysicists with required computational capabilities to study evolution stars...
Background: The O17(p,γ)F18 reaction affects the production of key isotopes (e.g., F18 and O18) in explosive hydrogen burning that powers classical novae. Under these conditions, rate is dominated by contributions from a narrow resonance at Ec.m.=183keV combined direct capture low-energy tails broad resonances. At present, astrophysical not well constrained because lack data energy region appropriate to Purpose: This study aims measurement cross section order determine its temperature...
High-resolution spectroscopy has revealed large concentrations of CNO and sometimes other intermediate-mass elements in the shells ejected during nova outbursts, suggesting that solar composition material transferred from secondary mixes with outermost layers underlying white dwarf thermonuclear runaway. Multidimensional simulations have shown Kelvin-Helmholtz instabilities provide self-enrichment accreted envelope dwarf, at levels agree observations. However, Eulerian time-explicit nature...
The production of 7Li and 7Be during the explosive hydrogen burning that occurs in nova explosions is computed by means a hydrodynamic code able to treat both accretion explosion stages. Large overproduction factors with respect solar abundances are obtained, exact value depending mainly on chemical composition envelope. Although final ejected masses small, these results indicate novae can contribute enrichment interstellar medium. Furthermore, since decays emitting gamma ray (478 keV),...
Classical novae emit gamma-ray radiation at 511 keV and below (with a cutoff around 20-30 keV), related to positron annihilation its Comptonization in the expanding envelope. This emission has been elusive up now because it occurs epochs well before maximum optical luminosity, but could be detected by some sensitive instrument on board satellite, provided that nova is close enough observed right moment. The detection of this emission, which challenge for current future instruments, would...
The long-lived radioactive nuclide 22Na (t1∕2=2.6yr) is an astronomical observable for understanding the physical processes of oxygen-neon novae. Yields in these events are sensitive to unknown total rate 21Na(p,γ)22Mg reaction. Using a high intensity 21Na beam at TRIUMF−ISAC facility, strengths seven resonances 22Mg, potential astrophysical importance, have been directly measured center mass energies from Ec.m.=200 1103keV. We report results obtained and their respective contributions novae...
The strength of the Ec.m. = 184 keV resonance in 26gAl(p, gamma)27 reaction has been measured inverse kinematics using DRAGON recoil separator at TRIUMF's ISAC facility. We measure a value omega gamma 35 +/- 7 microeV and energy 1 keV, consistent with p-wave proton capture into 7652(3) state 27Si, discuss implications these values for 26GAl nucleosynthesis typical oxygen-neon white-dwarf novae.
Nucleosynthesis in type I X-ray bursts may involve up to several thousand nuclear processes. The majority of these processes have only been determined theoretically due the lack sufficient experimental information. Accurate reaction $Q$-values are essential for reliable theoretical estimates rates. Those reactions with small ($<1$ MeV) particular interest environments as they represent waiting points a continuous abundance flow toward heavier-mass nuclei. To explore nature points, we...