Lithium is one of the few primordially produced elements .
The value of the primordial Li is taken to be that observed in metal–poor dwarfs , where it is not contaminated by stellar Li sources which act on longer time scales .
The atmospheric abundance is currently derived from the LiI \lambda \lambda 6707 \AA~ { } resonance transition and the validity of the models employed has been questioned \markcite k95 ( Kurucz 1995 ) .
In this letter we report the first detection of the Li I \lambda \lambda 6104 \AA~ { } 2 ^ { 2 } P - 3 ^ { 2 } D subordinate transition in the prototype population II star HD 140283 .
The same Li abundance of ( Li/H ) = 1.4 \times 10 ^ { -10 } is found consistent with both the resonance and subordinate lines .
The two lines form at different depths in the atmosphere implying that the 1-D homogeneous atmospheric models used in the abundance determination are essentially correct .
When coupled with the standard big bang yields , the Li in the halo dwarfs provides two solutions for the baryon-to-photon ratio \eta _ { 10 } = n _ { b } / n _ { \gamma } \times 10 ^ { 10 } and for the present baryon density \Omega _ { b } h _ { 70 } ^ { 2 } = 0.0748 \eta _ { 10 } : a ) a first solution at \eta _ { 10 } \approx 1.8 , consistent with the \eta _ { 10 } implied by the high deuterium values D / H \approx 2 \times 10 ^ { -4 } observed in some quasar absorption systems \markcite webb ( Webb et al 1997 ) and b ) a second solution at \eta _ { 10 } \approx 4 which is consistent , within the errors , with the low deuterium D/H = 3.4 \times 10 ^ { -5 } measured in other quasar absorption systems \markcite burles ( Burles & Tytler 1998 ) .