The radionuclide 22Na is a potential astronomical observable that is expected to be produced in classical novae in quantities that depend on the thermonuclear rate of the 22Na(p,γ)23Mg reaction. We have measured the strengths of low-energy 22Na(p,γ)23Mg resonances directly and absolutely using a radioactive 22Na target. We find the strengths of resonances at Ep=213, 288, 454, and 610 keV to be higher than previous measurements by factors of 2.4-3.2, and we exclude important contributions to the rate from proposed resonances at Ep=198, 209, and 232 keV. The 22Na abundances expected in the ejecta of classical novae are reduced by a factor of ≈2.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevLett.105.152501 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Search for Na in novae supported by a novel method for measuring femtosecond nuclear lifetimes.
Nat Commun
September 2023
Irfu, CEA, Université Paris-Saclay, Gif-sur-Yvette, France.
Classical novae are thermonuclear explosions in stellar binary systems, and important sources of Al and Na. While γ rays from the decay of the former radioisotope have been observed throughout the Galaxy, Na remains untraceable. Its half-life (2.
View Article and Find Full Text PDFConsolidation of : new classification into eight sections with 37 species and reinstatement of the genera and .
Stud Mycol
September 2022
The Czech Academy of Sciences, Institute of Microbiology, Laboratory of Fungal Genetics and Metabolism, 142 20 Prague 4, Czech Republic.
Article Synopsis
- The text discusses a little-understood group of soil- and wood-inhabiting fungi that reproduce through a rare process involving multiple locations and were previously classified into three sections, but recent studies show this classification is outdated.
- A new classification proposal is introduced, recognizing these fungi as a polythetic genus with 37 species divided into eight sections, alongside the reclassification of some species into a new genus.
- Additionally, the study highlights the ecological role of these fungi, noting their common presence in soil, association with forest habitats, and sensitivity to climate, supported by data from the GlobalFungi database.
X-ray detection of a nova in the fireball phase.
Nature
May 2022
Institut für Astronomie und Astrophysik, Kepler Center for Astro and Particle Physics, Eberhard Karls Universität, Tübingen, Germany.
Novae are caused by runaway thermonuclear burning in the hydrogen-rich envelopes of accreting white dwarfs, which leads to a rapid expansion of the envelope and the ejection of most of its mass. Theory has predicted the existence of a 'fireball' phase following directly on from the runaway fusion, which should be observable as a short, bright and soft X-ray flash before the nova becomes visible in the optical. Here we report observations of a bright and soft X-ray flash associated with the classical Galactic nova YZ Reticuli 11 h before its 9 mag optical brightening.
View Article and Find Full Text PDFAn evolutionary system of mineralogy. Part I: Stellar mineralogy (>13 to 4.6 Ga).
Am Mineral
April 2020
Earth and Planets Laboratory, Carnegie Institution for Science, 5251 Broad Branch Road NW, Washington, DC 20015, U.S.A.
Minerals preserve records of the physical, chemical, and biological histories of their origins and subsequent alteration, and thus provide a vivid narrative of the evolution of Earth and other worlds through billions of years of cosmic history. Mineral properties, including trace and minor elements, ratios of isotopes, solid and fluid inclusions, external morphologies, and other idiosyncratic attributes, represent information that points to specific modes of formation and subsequent environmental histories-information essential to understanding the co-evolving geosphere and biosphere. This perspective suggests an opportunity to amplify the existing system of mineral classification, by which minerals are defined solely on idealized end-member chemical compositions and crystal structures.
View Article and Find Full Text PDFA recurrent nova super-remnant in the Andromeda galaxy.
Nature
January 2019
Physics Department, Lancaster University, Lancaster, UK.
The accretion of hydrogen onto a white dwarf star ignites a classical nova eruption-a thermonuclear runaway in the accumulated envelope of gas, leading to luminosities up to a million times that of the Sun and a high-velocity mass ejection that produces a remnant shell (mainly consisting of insterstellar medium). Close to the upper mass limit of a white dwarf (1.4 solar masses), rapid accretion of hydrogen (about 10 solar masses per year) from a stellar companion leads to frequent eruptions on timescales of years to decades.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!