Context : HIP100963 was one of the first solar twins identified .
Although some high-precision analyses are available , a comprehensive high-precision study of chemical elements from different nucleosynthetic sources is still lacking from which to obtain potential new insights on planets , stellar evolution , and Galactic chemical evolution ( GCE ) .

Aims : We analyze and investigate the origin of the abundance pattern of HIP 100963 in detail , in particular the pattern of the light element Li , the volatile and refractory elements , and heavy elements from the s - and r -processes .

Methods : We used the HIRES spectrograph on the Keck I telescope to acquire high-resolution ( R \approx 70000 ) spectra with a high signal-to-noise ratio ( S/N \approx 400 - 650 per pixel ) of HIP 100963 and the Sun for a differential abundance analysis .
We measured the equivalent widths ( EWs ) of iron lines to determine the stellar parameters by employing the differential spectroscopic equilibrium .
We determined the composition of volatile , refractory , and neutron-capture elements through a differential abundance analysis with respect to the Sun .

Results : The stellar parameters we found are T _ { eff } = 5818 \pm 4 K , log g = 4.49 \pm 0.01 dex , v _ { t } = 1.03 \pm 0.01 { km { s } } ^ { -1 } , and [ Fe/H ] = - 0.003 \pm 0.004 dex .
These low errors allow us to compute a precise mass ( 1.03 ^ { +0.02 } _ { -0.01 } { M _ { \odot } } ) and age ( 2.0 \pm 0.4 Gyr ) , obtained using Yonsei-Yale isochrones .
Using our [ Y/Mg ] ratio , we have determined an age of 2.1 \pm 0.4 Gyr , in agreement with the age computed using isochrones .
Our isochronal age also agrees with the age determined from stellar activity ( 2.4 \pm 0.3 Gyr ) .
We study the abundance pattern with condensation temperature ( { T _ { cond } } ) taking corrections by the GCE into account .
We show that the enhancements of neutron-capture elements are explained by contributions from both the s - and r -process .
The lithium abundance follows the tight Li-age correlation seen in other solar twins .

Conclusions : We confirm that HIP 100963 is a solar twin and demonstrate that its abundance pattern is about solar after corrections for GCE .
The star also shows enrichment in s - and r -process elements , as well as depletion in lithium that is caused by stellar evolution .