Employing high resolution spectra obtained with the near-UV sensitive detector on the Keck I HIRES , supplemented by data obtained with the McDonald Observatory 2-d coudé , we have performed a comprehensive chemical composition analysis of the bright r -process-rich metal-poor red giant star HD 221170 .
Analysis of 57 individual neutral and ionized species yielded abundances for a total of 46 elements and significant upper limits for an additional five .
Model stellar atmosphere parameters were derived with the aid of \sim 200 Fe-peak transitions .
From more than 350 transitions of 35 neutron-capture ( Z > 30 ) species , abundances for 30 neutron-capture elements and upper limits for three others were derived .
Utilizing 36 transitions of La , 16 of Eu , and seven of Th , we derive ratios of log \epsilon ( Th/La ) = - 0.73 ( \sigma = 0.06 ) and log \epsilon ( Th/Eu ) = - 0.60 ( \sigma = 0.05 ) , values in excellent agreement with those previously derived for other r -process-rich metal-poor stars such as CS 22892-052 , BD+17 ^ { \circ } 3248 , and HD 115444 .
Based upon the Th/Eu chronometer , the inferred age is 11.7 \pm 2.8 Gyr .
The abundance distribution of the heavier neutron-capture elements ( Z \geq 56 ) is fit well by the predicted scaled solar system r -process abundances , as also seen in other r -process-rich stars .
Unlike other r -process-rich stars , however , we find that the abundances of the lighter neutron-capture elements ( 37 < Z < 56 ) in HD 221170 are also statistically in better agreement with the abundances predicted for the scaled solar r -process pattern .