1) La descarga del recurso depende de la página de origen
2) Para poder descargar el recurso, es necesario ser usuario registrado en Universia


Opción 1: Descargar recurso

Opción 2: Descargar recurso

Detalles del recurso

Descripción

Gamma-ray telescopes in orbit around the earth are searching for evidence of the elusive radionuclide 22Na produced in novae. Previously published uncertainties in the dominant destructive reaction, 22Na(p,γ)23Mg, indicated new measurements in the proton energy range of 150 to 300 keV were needed to constrain predictions. We have measured the resonance strengths, energies, and branches directly and absolutely by using protons from the University of Washington accelerator with a specially designed beam line, which included beam rastering and cold vacuum protection of the 22Na implanted targets. The targets, fabricated at TRIUMF-ISAC, displayed minimal degradation over a ∼20 C bombardment as a result of protective layers. We avoided theneed to know the absolute stopping power, and hence the target composition, by extracting resonance strengths from excitation functions integrated over proton energy. Our measurements revealed that resonance strengths for Ep = 213, 288, 454, and 610 keV are stronger by factors of 2.4–3.2 than previously reported. Upper limits have been placed on proposed resonances at 198, 209, and 232 keV. These substantially reduce the uncertaintyin the reaction rate. We have re-evaluated the 22Na(p,γ) reaction rate, and our measurements indicate the resonance at 213 keV makes the most significant contribution to 22Na destruction in novae. Hydrodynamicsimulations including our rate indicate that the expected abundance of 22Na ejecta from a classical nova is reduced by factors between 1.5 and 2, depending on the mass of the white-dwarf star hosting the nova explosion.

Pertenece a

RECERCAT  

Autor(es)

José Pont, Jordi -  Caggiano, J. A. -  Hutcheon, D. A. -  Vockenhuber, C. -  Buchmann, L. -  Sallaska, A.L. -  Wrede, C. -  Garcia, A. -  Storm,, D. W. -  Brown, T. A. D. -  Ruiz, C. -  Snover, K.A. -  Ottewell, D. - 

Id.: 54482485

Idioma: inglés  - 

Versión: 1.0

Estado: Final

Tipo:  0 p. - 

Palabras claveÀrees temàtiques de la UPC -  Física -  Astronomia i astrofísica - 

Tipo de Interactividad: Expositivo

Nivel de Interactividad: muy bajo

Audiencia: Estudiante  -  Profesor  -  Autor  - 

Estructura: Atomic

Coste: no

Copyright: sí

: Open Access

Formatos:  0 p. - 

Requerimientos técnicos:  Browser: Any - 

Fecha de contribución: 22-sep-2011

Contacto:

Localización:
* Sallaska, A. [et al.]. Absolute determination of the Na-22(rho, gamma)Mg-23 reaction rate in novae. "Physical review C", 23 Març 2011, vol. 83, núm. 3.
* 0556-2813
* 10.1103/PhysRevC.83.034611

Otros recursos del mismo autor(es)

  1. Reviewed by: identification of virulence factors required for respiratory melioidosis using Tn-seq mutagenesis. F...
  2. Research Article Microencapsulation, Chemical Characterization, and Antimicrobial Activity of Mexican (Lippia graveolens H.B.K.) and European (Origanum vulgare L.) Oregano Essential Oils Copyright © 2014 Elvia Hernández-Hernández et al. This is an open access article distributed under...
  3. RESEARCH ARTICLE Amniotic Membrane Modifies the Genetic Program Induced by TGFß, Stimulating Keratinocyte Proliferation and Migration in Chronic Wounds Background Post-traumatic large-surface or deep wounds often cannot progress to reepithelialisation ...
  4. RESEARCH ARTICLE Inhibition of Staphylococcus aureus Adhesion to the Surface of a Reticular Heavyweight Polypropylene Mesh Soaked in a Combination of Chlorhexidine and Allicin: An In vitro Study
  5. An Interactive Internet-Based Continuing Education Course on Sexually Transmitted Diseases for Physicians and Midwives in Peru Background: Clinicians in developing countries have had limited access to continuing education (CE) ...

Otros recursos de la misma colección

No existen otros recursos

Aviso de cookies: Usamos cookies propias y de terceros para mejorar nuestros servicios, para análisis estadístico y para mostrarle publicidad. Si continua navegando consideramos que acepta su uso en los términos establecidos en la Política de cookies.