Explosive hydrogen burning
Public Deposited- Creator
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Champagne, A.E.
- College of Arts and Sciences, Department of Physics and Astronomy
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Wiescher, M.
- Other Affiliation: University of Notre Dame
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Champagne, A.E.
- Abstract
- Under astrophysical conditions of extreme temperature and density, nuclear reactions can occur with rates that are comparable to a dynamical free-fall time, i.e. on the order of seconds. Explosive hydrogen burning will take place in a number of sites, most notably in cataclysmic binary systems (including novae and some x-ray bursts), and during Type II supernovae. The former objects are thought to be thermonuclear outbursts triggered by mass accretion onto the surface of either a white dwarf or a neutron star. A knowledge of the relevant nuclear reaction cross sections is therefore critical to our understanding of the outburst phenomenon itself. In particular, this information determines the amount of energy generated to power the outburst and the inventory of elements produced. These results may be compared with direct observations to provide a tight constraint on models of these systems. Much useful information can be obtained from the nucleosynthesis itself. For example, measurements of absolute and relative elemental abundances, combined with nucleosynthesis calculations , could yield information regarding the physical conditions during the explosion. Also, if a detectable amount of a gamma-ray emitter such as 22Na or 26 Al is produced, then observations of the gamma-ray flux over time may shed some light on how the ejecta are mixed into the interstellar medium . The nuclei of active galaxies are thought to be powered by a similar mechanism, in this case mass accretion by massive black holes. As a result, much of what we learn by studying cataclysmic binaries might also be applied to models of active galaxies. In the case of supernovae, explosive hydrogen burning is incidental to the underlying explosion mechanism. However, nucleosynthetic yields are again useful in probing the explosion. In addition , since supernovae are major sources of heavy elements, explosive nucleosynthesis is responsible for much of galactic chemical evolution.
- Date of publication
- 1992
- Keyword
- DOI
- Identifier
- Resource type
- Article
- Rights statement
- In Copyright
- Journal title
- Annual Review of Nuclear and Particle Science
- Journal volume
- 42
- Journal issue
- 1
- Page start
- 39
- Page end
- 76
- Language
- English
- Version
- Publisher
- ISSN
- 0163-8998
- Publisher
- Annual Reviews Inc.
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