Nuclear astrophysics

Dept, of Physics and Astronomy and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824, USA... 

Among a number of indirect methods which have been suggested for nuclear astrophysics applications the Trojan Horse Method (THM) is particularly suitable in the case of (p,a), (n,a),(n,p) reactions. In the following we will not discuss in details the method, so we refer to [3] for further details. 

D. D. Clayton, Principles of Stellar Evolution and Nucleosynthesis, McGraw-Hill 1968, University of Chicago Press 1984. This classic text is particularly well written and gives more accurate and rigorous arguments for results derived here often in a somewhat heuristic manner. A more up-to-date (though in some ways less complete) description of nuclear astrophysics is given in... 

A more up-to-date treatment of many aspects of stellar evolution and nuclear astrophysics is available in the book by... 

They have been thrust to the forefront of cosmology, a boon for nuclear astrophysics The satellite INTEGRAL, dedicated to nuclear gamma-ray astronomy and on the point of spreading its wings, carries all the hopes and aspirations of the scientific community to which 1 belong. 

Today, physical chemistry has accomplished its great task of elucidating the microcosmos. The existence, properties and combinatory rules for atoms have been firmly established. The problem now is to work out where they came from. Their source clearly lies outside the Earth, for spontaneous (cold) fusion does not occur on our planet, whereas radioactive transmutation (breakup or decay), e.g. the decay of uranium to lead, is well known to nuclear geologists. The task of nuclear astrophysics is to determine where and how each species of atomic nucleus (or isotope) is produced beyond the confines of the Earth. 

Titanium-44 is thus an isotope of considerable astrophysical importance. Detection of its characteristic gamma line has aroused great enthusiasm amongst the nuclear astrophysics community because this isotope supplies precious clues as to the explosion mechanisms operating inside massive stars. Indeed, it allows us to determine the exact boundary between the part of the star which is imploding, to end up as a neutron star, and the part which is ejected and flies out into space, loaded with atomic nuclei manufactured by the star. It also provides... 

The path that leads from the multitude of anonymous and abstract elementary particles generated in the original explosion to the grass in the meadows, to the rain and the wind, to the infinite variety of shapes and states, to the profusion of feelings, must necessarily pass through the stars. Stars are an essential link between the primordial raw material that came out of the Big Bang and complex material with the ability to think. Nuclear astrophysics is the bridge between elementary particle physics and life. 

Star, driving force behind the chemical evolution of the galaxies, mother of atoms and of all life, gentle or explosive, let us seek to become better acquainted. Eor it is one thing to observe and record the state of atomic matter in the Universe, and quite another to explain it. It is to this Herculean task that nuclear astrophysics dedicates it best troops. And the starting-point for each sally is the Sun, our personal reference. 

Everywhere in the Universe the same patterns reappear atoms in the microcosm and stars in the macrocosm. Atoms and stars are related, for the star is the mother of atoms. This statement sums up one of the great discoveries of the twentieth century. The task of nuclear astrophysics is to draw in the details of the relationship. The creation of matter has become a subject of scientific research. The source of most atoms, or rather their nuclei, is the stars. 

Like chemistry, nuclear astrophysics is a combinatorial art. Nuclear reactions are written down like chemical reactions, replacing atoms with nuclei. 

But do we know what cunning enterprise the sky has been engaged upon in order to prepare and mould this bounteous carbon and then to extract it from the great stellar furnace We shall once again follow through the main avenues of nuclear astrophysics, but this time considering life as we know it, or rather, one of the conditions that makes it feasible carbon. 

Needless to say, nuclear astrophysics does not limit itself to the chemical evolution of the Milky Way, but seeks to bestow a cosmic dimension upon its quest for the origin and evolution of the elements. Ever beclouded by the earliest times, the time of the genesis, the astrophysical spirit infiltrates the turbulent youth of the galaxies, going back to the stormy days of their early childhood. 

The demonstration that stars are capable of such nuclear fertihty is based upon a combination of knowledge from what appear to be widely separated areas of physics. One of these concerns the internal structure of stars, telling us the temperature and pressure at different depths. The other concerns the probabilities at different energies of all the possible reactions between various nuclei, and between those nuclei and protons or neutrons. In the latter case, the acquisition of the relevant data was greatly accelerated by the Second World War. The beauty of nuclear astrophysics rests upon the success of this marriage and the complementarity of the two disciplines it brings together. The nuclear butterfly has returned to its stellar chrysalis. 

Arnould M. Takahashi K. (1999) Nuclear astrophysics. Rep. Prog. Phys. 62, 393. Audouze J. (1998) L Univers . Que sais-je (Presses Universitaires de France, Paris). Audouze J. Cazenave M. (2000) L Homme dans ses univers (Albin Michel, Paris). Audouze J. Israel G. (eds.) (1983) The Cambridge Atlas of Astronomy (Cambridge University Press, Cambridge). 

Rolfs C.E. Rodney W.S. (1998) Cauldrons in the Cosmos Nuclear Astrophysics (University of Chicago Press, Chicago). 

Cameron, A. G. W. (1957) Stellar Evolution, Nuclear Astrophysics, and Nucleogenesis (CRL-41 AECL-454). Chalk River, Ontario Atomic Energy of Canada, Ltd. 

Wasserburg, G. J. and Papanastassiou, D. A. (1982) Some short-lived nuclides in the early solar system a connection with the placental ISM. In Essays in Nuclear Astrophysics, eds. Barnes, C. A., Clayton, D.D. and Schramm, D.N. Cambridge Cambridge University Press, pp. 77-140. A good review of the early history of chronology using short-lived radionuclides. 

This chapter concerns the fields that use inorganic mass spectrometry to investigate the composition and evolution of matter in the universe and in the solar system. Cosmochemistry is related to nuclear astrophysics, because almost all the chemical elements were synthesized by nuclear reactions in the interior of stars.1 Mass spectrometric analyses of elemental composition, the distribution and variation of isotope abundances are very helpful, especially for cosmochronological studies, in order to explain the formation, history and evolution of stars in our universe and to understand the chemical and nuclear processes. 

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