摘要：Context. HIP 100963 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 ≈
70 000) spectra with a high signal-to-noise ratio (S/N ≈
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 Teff = 5818 ± 4
K, log g = 4.49 ±
0.01 dex, vt = 1.03 ±
0.01km
s-1, and [Fe/H] =
−0.003 ± 0.004 dex. These low errors allow us to compute a precise
mass (1.03+0.02-0.01 M⊙) and age
(2.0 ± 0.4 Gyr), obtained
using Yonsei-Yale isochrones. Using our [Y/Mg] ratio, we have determined an age of
2.1 ± 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 ±
0.3 Gyr). We study the abundance pattern with condensation temperature
(Tcond) 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.
关键词：Sun: abundances;stars: abundances;stars: AGB and post-AGB;stars: fundamental parameters;stars: solar-type;planetary systems
