Galactic Cosmic Rays from Superbubbles and the Abundances of Lithium, Beryllium, and Boron
نویسندگان
چکیده
In this article we study the galactic evolution of the LiBeB elements within the framework of a detailed model of the chemical evolution of the Galaxy that includes galactic cosmic ray nucleosynthesis by particles accelerated in superbubbles. The chemical composition of the superbubble consists of varying proportions of ISM and freshly supernova synthesized material. The observational trends of LiBeB evolution are nicely reproduced by models in which GCR come from a mixture of 25% of supernova material with 75% of ISM, except for Li, for which maybe an extra source is required at low metallicities. To account for Li evolution several additional sources have been considered (neutrino–induced nucleosynthesis, nova outbursts, C–stars). The model fulfills the energetic requirements for GCR acceleration.
منابع مشابه
Measurements of the Isotopes of Lithium, Beryllium, and Boron from ACE/CRIS
The isotopes of lithium, beryllium, and boron (LiBeB) are known in nature to be produced primarily by CNO spallation and a a fusion from interactions between cosmic rays and interstellar nuclei. While the dominant source of LiBeB isotopes in the present epoch is cosmic-ray interactions, other sources are known to exist, including the production of Li from big bang nucleosynthesis. Precise obser...
متن کاملCosmic Ray Models for Early Galactic Lithium, Beryllium, and Boron Production
To understand better the early galactic production of Li, Be, and B by cosmic ray spallation and fusion reactions, the dependence of these production rates on cosmic ray models and model parameters is examined. The sensitivity of elemental and isotopic production to the cosmic ray pathlength magnitude and energy dependence, source spectrum, spallation kinematics, and cross section uncertainties...
متن کاملLight Element Evolution in the Galactic Halo
Abstract. Using a time-dependent Galactic Cosmic Ray flux proportional to the halo Star Formation Rate and including astration and neutrino-induced nucleosynthesis, we have studied the evolution of lithium, beryllium and boron in the halo. Our results set limits to the production of LiBeB by the neutrino-induced nucleosynthesis in massive stars, in order to reproduce the observed constancy of B...
متن کاملThe Source of Cosmic Rays: 3. Supernova Grain Composition
We show that the expected composition of cosmic rays accelerated from the erosion products of fast supernova grains in the hot interstellar medium (HISM) of ejecta enriched superbubbles, where the bulk ( 85%) of Galactic supernovae occur, is consistent with the currently available cosmic ray data. In particular, we show that if the cosmic ray metals come from the sputtering of fast refractory g...
متن کامل24 . Cosmic rays 1 24 . COSMIC RAYS
The cosmic radiation incident at the top of the terrestrial atmosphere includes all stable charged particles and nuclei with lifetimes of order 106 years or longer. Technically, “primary” cosmic rays are those particles accelerated at astrophysical sources and “secondaries” are those particles produced in interaction of the primaries with interstellar gas. Thus electrons, protons and helium, as...
متن کامل