Lithium astrophysics

Lithium is an element of interest in astrophysics, owing to the marked variations in Li abundance and isotopic composition of materials emanating from different sources in the cosmos. The development of the terrestrial or Solar system Li isotopic compositions, which, to the limit of our current rmderstanding, are quite different from values predicted for nucleosynthetic or interstellar Li, remains a puzzle for active astronomical research. 

A large increase in the O/Fe ratio in stars at low metallicity was reported by Israelian et al. in 1998 and by Boesgaard et al. in 1999, contradicting earlier data which suggested an approximately constant O/Fe ratio. Now oxygen is particularly relevant to the astrophysics of cosmic rays. This is because spallation products under collision include the light nuclei lithium, beryllium and boron. 

DIP Lithium isotope ratios are important to medicine, geology, astrophysics, and nuclear chemistry. Measurements of the 6Li/7Li ratio in a Standard Reference Material are given here.12 Do the two methods give statistically equivalent results ... 

The observations of the lithium resonance line at x6708.8 A were carried out with a SIT vidicon detector attached to the coudi spectrometer of the 1.5 m telescope of the Tartu Astrophysical Observatory. The sample of stars observed consists of 70 K0 - K5 and 75 MO - M4 giants. A set of spectra of K giants with different strengths of lithium resonance doublet is shown in Fig. 1. 

From the isotopic decomposition ofnormal lithium onefinds thatthemass-6 isotope, 6Li, is the lesser abundant of lithium s two isotopes 7.5% of terrestrial Li. Lithium presents some of the most interesting abundance questions in astrophysics (see also 7Li). Using the total abundance of elemental Li = 57.1 per million silicon atoms in solar-system matter, this isotope has... 

Lithium has two stable isotopes, 6Li and 7Li, both of which can serve as indicators of important astrophysical processes. In particular, the ratio of these isotopes can provide clues about interstellar production of the light elements as well as information on convection in stellar atmospheres. 

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