High precision analysis of the solar twin HIP 100963

TL;DR

This study precisely characterizes the solar twin HIP 100963 using high-resolution spectroscopy, confirming its similarity to the Sun and analyzing its detailed chemical composition, age, and evolutionary status.

Contribution

The paper provides the most precise stellar parameters and chemical abundances for HIP 100963, demonstrating its status as a solar twin with detailed abundance patterns including neutron-capture elements.

Findings

HIP 100963 has stellar parameters very close to the Sun.

The star's age is approximately 2.0 Gyr, confirmed by multiple methods.

Enrichment in s- and r-process elements and lithium depletion consistent with stellar evolution.

Abstract

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 $T_{\rm{eff}}=5818 \pm 4$ K, log $g = 4.49 \pm 0.01$ dex, $v_{t} = 1.03 \pm 0.01 $ $\rm{km\ {s}}^{-1}$ , 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 ($\rm{T_{cond}}$) 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.