Nuclear gamma-ray line spectroscopy provided direct evidence for the production Fe in a supernova and it is expected that observations of lines from a nearby nova will provide information on nucleosynthesis in stars. However detection of gamma-ray lines from main sequence stars other than the Sun can only be expected with significant improvement in sensitivity. Gamma-ray observations of solar flares provide measurements of the composition and spectra of accelerated ions their transport and scattering and the composition density and temperature of the ambient plasma where the particles interact. Some discoveries from these observation are: 1) enhancement in the concentration of low FIP elements in the chromosphere 2) a highly variable accelerated ion to electron ratio and flares where accelerated-ion energy exceeds that in electrons 3) accelerated alpha/proton ratio > 0.1 and accelerated 3He enhanced by >1000 over its photospheric value (measured using gamma rays) 4) broadened 511 keV annihilation line and detection of the positronium continuum 5) significant pitch-angle scattering of accelerated particles in coronal magnetic loops 6) flare-accelerated Fe enhancements consistent with those observed in solar energetic particles and 7) flares can account for the 6Li in the solar wind.
Stars as Suns : Activity, Evolution and Planets
- Pub Date:
- January 2004