  We present the first detailed chemical abundance analysis of the old 8.2 Gyr
solar twin, HIP 102152. We derive differential abundances of 21 elements
relative to the Sun with precisions as high as 0.004 dex ($\lesssim$1%), using
ultra high-resolution (R = 110,000), high S/N UVES spectra obtained on the
8.2-m Very Large Telescope. Our determined metallicity of HIP 102152 is [Fe/H]
= -0.013 $\pm$ 0.004. The atmospheric parameters of the star were determined to
be 54 K cooler than the Sun, 0.09 dex lower in surface gravity, and a
microturbulence identical to our derived solar value. Elemental abundance
ratios examined vs. dust condensation temperature reveal a solar abundance
pattern for this star, in contrast to most solar twins. The abundance pattern
of HIP 02152 appears to be the most similar to solar of any known solar twin.
Abundances of the younger, 2.9 Gyr solar twin, 18 Sco, were also determined
from UVES spectra to serve as a comparison for HIP 102152. The solar chemical
pattern of HIP 102152 makes it a potential candidate to host terrestrial
planets, which is reinforced by the lack of giant planets in its terrestrial
planet region. The following non-local thermodynamic equilibrium Li abundances
were obtained for HIP 102152, 18 Sco, and the Sun: log $\epsilon$ (Li) = 0.48
$\pm$ 0.07, 1.62 $\pm$ 0.02, and 1.07 $\pm$ 0.02, respectively. The Li
abundance of HIP 102152 is the lowest reported to date for a solar twin, and
allows us to consider an emerging, tightly constrained Li-age trend for solar
twin stars.
