Credit: P. Martin et al.; ESA
Aluminum Sure Can
Stars more massive than about 8 times the mass of the Sun make up only an exceedingly small fraction of the stars in a typical spiral galaxy. Despite their paucity, these stars play an important role in creating complex atoms and dispersing them into space. Needed stuff like carbon, oxygen and nitrogen, and useful stuff like iron and aluminum. Elements like aluminum are cooked up in these massive stars deep in their stellar cores, but can be gradually dredged up to the stellar surface and blown outwards via photon-driven stellar winds. Or this enriched material can be thrown outward when the star runs out of thermonuclear fuel and explodes. This dispersal process, vital for the existence of the material Universe and life itself, can be effectively studied by measuring the peculiar radioactive emission given off from this material. Gamma-ray emission lines of aluminum, which are particularly long-lasting, are particularly prized by astronomers as a tracer of this entire process. The graph above shows the predicted change in the of the amount of a particular isotope of aluminum, Al26, for a region of the Milky Way which is particularly rich in massive stars. The yellow band is the Al26 abundance for this region as determined by the INTEGRAL Gamma-ray laboratory. The overlap between the observed abundance and the predicted model re-assures astronomers of our understanding of the delicate ties between stellar evolution and Galactic chemical evolution.
Published: May 24, 2010
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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 28-May-2010 18:33:43 EDT