Chemical evolution of Mg isotopes versus the time variation of the fine structure constant.
We show that the synthesis of (25,26)Mg at the base of the convective envelope in low-metallicity asymptotic giant branch stars can produce the isotopic ratios needed to explain the low-z subset (with z<1.8) of the many-multiplet data from quasar absorption systems without invoking a time variation of the fine structure constant. This is supported by observations of high abundances of the neutron-rich Mg isotopes in metal-poor globular-cluster stars. We conclude that the quasar absorption spectra may be providing interesting information on the nucleosynthetic history of such systems.
Ashenfelter
T
T
Department of Physics, Center for Astrophysics, University of Notre Dame, Notre Dame, IN 46556, USA.
Mathews
Grant J
GJ
Olive
Keith A
KA