  We have obtained a high resolution (R~90,000) spectrum of the carbon- and
s-process-element-rich, very metal-poor ([Fe/H]=-2.7) subgiant LP625-44, as
well as that of HD140283 (a metal-poor subgiant with normal abundance ratio)
for comparison, with the High Dispersion Spectrograph (HDS) for the Subaru
Telescope for detailed abundance study. The oxygen abundance derived from the O
I triplet around 7770A is uncertain, but the excess of oxygen in LP625-44 seems
remarkable (perhaps by nearly a factor 10), in comparison with that of HD140283
derived from the same lines. The Na enhancement in LP625-44 is by about a
factor 50, suggesting hydrogen burning in the 22Ne-rich layer in an asymptotic
giant branch star which produces the abundance pattern of this object. In our
new spectrum of LP625-44, the Pb I lambda 3683A line has been detected, as well
as the Pb I lambda 4057A line which has already been studied, confirming the Pb
abundance (log epsilon(Pb)~1.9) derived by the previous work. The abundance
ratio of s-process elements at the second peak (e.g., La, Ce and Nd) to that at
the third peak (Pb) in LP 625-44 is significantly higher (by a factor 5) than
that in other three s-process element-rich objects recently studied by van Eck
et al.. Recent theoretical works have modeled the s-process nucleosynthesis in
the radiative layer of asymptotic giant branch stars in the inter-pulse phase,
and the above results means that these processes produced a large scatter in
the abundance ratios. Another possiblity is that different processes (e.g.,
s-process nucleosynthesis during thermal pulses) have contributed to heavy
elements in the early Galaxy.
