scholarly journals Nucleosynthetic Activity of WR Stars: Implications for 26Al in the Galaxy and Isotopic Anomalies in Cosmic Rays and the Early Solar System

1991 ◽  
Vol 143 ◽  
pp. 550-550 ◽  
Author(s):  
N. Prantzos
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Observational Data ◽  
Galactic Plane ◽  
Galactic Cosmic Rays ◽  
Early Solar System ◽  
The Galaxy ◽  
Isotopic Anomalies

The implications of the nucleosynthetic activity of WR stars are reassessed, in view of recent experimental and observational data. It is confirmed that WR stars may 1) contribute significantly (up to ~20%) to the ~3 M⊙ of 26Al detected in the galactic plane through its 1.8 MeV line, 2) be responsible for the isotopic anomalies of 22Ne and 25,26Mg, detected in galactic cosmic rays (GCR), and 3) be responsible for the inferred presence of 26Al and 107Pd in the early solar system (and, perhaps, some other nuclei as well).

scholarly journals Propagation Studies Related to the Origin of Cosmic Rays

1981 ◽  
Vol 94 ◽  
pp. 93-106
Author(s):  
R. Cowsik
Keyword(s):  
Solar Wind ◽  
Cosmic Rays ◽  
Solar System ◽  
Relative Abundance ◽  
Galactic Plane ◽  
Cosmic Ray ◽  
Accurate Method ◽  
Galactic Cosmic Rays ◽  
High Energies ◽  
The Galaxy

Propagation of cosmic rays is discussed with the intent of deriving results relevent to the origin of cosmic rays. Starting from a brief description of the methods for demodulating the effects of the solar wind on the spectra of particles, we describe an accurate method for correcting for spallation effects on the cosmic-ray nuclei during their transport from the sources subsequent to their acceleration. We present the composition of cosmic rays at the sources and discuss its implications to their origin. We discuss briefly the effects of stochastic acceleration in the interstellar medium on the relative spectra of primaries and secondaries in cosmic rays and show that the observation of decreasing relative abundance of secondaries with increasing energy rules out such phenomena for galactic cosmic rays. The spectrum of cosmic-ray electrons is discussed in terms of contributions from a discrete set of sources situated at various distances from the solar system on the galactic plane. We show that unless there are at least 3.104 sources actively accelerating cosmis rays in the Galaxy the spectrum of electrons would have a premature cut-off at high energies. Finally we point out some important questions that need to be clearly resolved for making further progress in the field.

scholarly journals On particle acceleration and transport in plasmas in the Galaxy: theory and observations

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Elena Amato ◽  
Sabrina Casanova
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Quality Data ◽  
Current Status ◽  
The Earth ◽  
The Galaxy ◽  
Formation And Evolution ◽  
Galaxy Assembly

Accelerated particles are ubiquitous in the Cosmos and play a fundamental role in many processes governing the evolution of the Universe at all scales, from the sub-AU scale relevant for the formation and evolution of stars and planets to the Mpc scale involved in Galaxy assembly. We reveal the presence of energetic particles in many classes of astrophysical sources thanks to their production of non-thermal radiation, and we detect them directly at the Earth as cosmic rays. In the last two decades both direct and indirect observations have provided us a wealth of new, high-quality data about cosmic rays and their interactions both in sources and during propagation, in the Galaxy and in the Solar System. Some of the new data have confirmed existing theories about particle acceleration and propagation and their interplay with the environment in which they occur. Some others have brought about interesting surprises, whose interpretation is not straightforward within the standard framework and may require a change of paradigm in terms of our ideas about the origin of cosmic rays of different species or in different energy ranges. In this article, we focus on cosmic rays of galactic origin, namely with energies below a few petaelectronvolts, where a steepening is observed in the spectrum of energetic particles detected at the Earth. We review the recent observational findings and the current status of the theory about the origin and propagation of galactic cosmic rays.

scholarly journals Composition and Galactic Confinement of Cosmic Rays

1971 ◽  
Vol 2 ◽  
pp. 740-756
Author(s):  
Maurice M. Shapiro
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Interstellar Space ◽  
Heavy Nuclei ◽  
High Energy Astrophysics ◽  
Transit Times ◽  
The Galaxy ◽  
Path Lengths

The ‘Galactic’ cosmic rays impinging on the Earth come from afar over tortuous paths, traveling for millions of years. These particles are the only known samples of matter that reach us from regions of space beyond the solar system. Their chemical and isotopic composition and their energy spectra provide clues to the nature of cosmic-ray sources, the properties of interstellar space, and the dynamics of the Galaxy. Various processes in high-energy astrophysics could be illuminated by a more complete understanding of the arriving cosmic rays, including the electrons and gamma rays.En route, some of theprimordialcosmic-ray nuclei have been transformed by collision with interstellar matter, and the composition is substantially modified by these collisions. A dramatic consequence of the transformations is the presence in the arriving ‘beam’ of considerable fluxes of purely secondary elements (Li, Be, B), i.e., species that are, in all probability, essentially absent at the sources. We shall here discuss mainly the composition of the arriving ‘heavy’ nuclei -those heavier than helium - and what they teach us about thesourcecomposition, the galactic confinement of the particles, their path lengths, and their transit times.

Galactic Cosmic Rays in the Solar System

1966 ◽  
Vol 145 ◽  
pp. 206 ◽  
Author(s):  
Vikram Sarabhai ◽  
G. Subramanian
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Galactic Cosmic Rays

scholarly journals Hydrogen molecular ions and the violent birth of the Solar System

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180403 ◽  
Author(s):  
Cecilia Ceccarelli ◽  
Cecile Favre ◽  
Ana López-Sepulcre ◽  
Francesco Fontani
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Past History ◽  
Classical Problem ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Molecular Ions ◽  
Observational Constraints ◽  
The Past ◽  
History Of

Many pieces of evidence indicate that the Solar System youth was marked by violent processes: among others, high fluxes of energetic particles (greater than or equal to 10 MeV) are unambiguously recorded in meteoritic material, where an overabundance of the short-lived 10 Be products is measured. Several hypotheses have been proposed to explain from where these energetic particles originate, but there is no consensus yet, mostly because of the scarcity of complementary observational constraints. In general, the reconstruction of the past history of the Solar System is best obtained by simultaneously considering what we know of it and of similar systems nowadays in formation. However, when it comes to studying the presence of energetic particles in young forming stars, we encounter the classical problem of the impossibility of directly detecting them toward the emitting source (analogously to what happens to galactic cosmic rays). Yet, exploiting the fact that energetic particles, such as cosmic rays, create H 3 + and that an enhanced abundance of H 3 + causes dramatic changes on the overall gas chemical composition, we can indirectly estimate the flux of energetic particles. This contribution provides an overview of the search for solar-like protostars permeated by energetic particles and the discovery of a protocluster, OMC-2 FIR4, where the phenomenon is presently occurring. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Atmospheres as a clue to the early Solar System

1988 ◽  
Vol 325 (1587) ◽  
pp. 569-582 ◽  
Keyword(s):  
Solar System ◽  
Observational Data ◽  
Terrestrial Planets ◽  
The Sun ◽  
Early Solar System ◽  
Secondary Formation ◽  
Planets And Satellites

Conditions that could have applied in the environments of the major planets when they were forming make it possible that the present icy mantles of the larger satellites were then oceans and vapour atmospheres encasing silicate—ferrous cores. The major constituents are explored by comparison with the present atmospheres of the terrestrial planets. It is further suggested that the primary condensations during the formation of the Solar System were the Sun and the major planets, and that the terrestrial planets and satellites were a secondary formation. Some observational data are offered in support of the arguments and future tests are suggested.

scholarly journals Radio Emission from Supernova Remnants

1996 ◽  
Vol 145 ◽  
pp. 333-340
Author(s):  
Richard G. Strom
Keyword(s):  
Cosmic Rays ◽  
Radio Emission ◽  
Supernova Remnants ◽  
Galactic Plane ◽  
Galactic Disk ◽  
Energy Content ◽  
Particle Energy ◽  
The Galaxy ◽  
Radio Frequencies ◽  
Shock Fronts

Most of the supernova remnants known in the Galaxy have only been detected at radio frequencies. The reason for this is absorption in the Galactic plane at both optical and X-ray wavelengths. All available evidence suggests that the shock fronts which accompany supernova remnants accelerate enough cosmic rays to GeV energies to produce readily detectable radio emission. This is fortunate, for it enables us to study remnants throughout the Galactic disk, although existing catalogues may be anywhere from 50 to 90 % incomplete. Cosmic rays and the magnetic fields in which they gyrate are the essential ingredients for producing the synchrotron radiation which is observed at radio frequencies. Various methods for estimating magnetic field strengths can be applied to a small number of remnants, and produce values not far from those based upon equipartition between the energy contents of particles and fields. From this, the particle energy content is derived for a number of objects.

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