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 102152 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 .