The SOL $\textit{(Solar Origin and Life)}$ Project: Detailed characterization of candidates for the ZAMS and Subgiant stages

TL;DR

This study identifies and characterizes stars similar to the Sun at different evolutionary stages, using spectroscopic, kinematic, and activity analyses to find candidates that match the Sun's properties at ZAMS and subgiant phases.

Contribution

The paper presents a successful method for selecting Sun-like stars at various evolutionary stages through comprehensive spectroscopic and activity-based analyses.

Findings

Identified three stars similar to the Sun at different stages.

Demonstrated the effectiveness of combined spectroscopic and activity analysis methods.

Provided candidates for future exoplanet habitability studies.

Abstract

The context of the Sun in the galactic neighborhood is not well understood, especially when we compare its physical properties to those of nearby stars. Thereby, we still cannot fully comprehend whether or not the Sun is a typical star. This work aims to identify and characterize stars aligned with the solar evolutionary track that could represent it at the ZAMS and subgiant stages. We performed a spectroscopic analysis of 18 photometrically selected candidates using high-resolution and high-SNR spectra as well as the classical spectroscopic method, based on the excitation and ionization equilibria of Fe I and Fe II lines. Additionally, we derived evolutionary parameters using isochrones, and kinematic parameters. We also estimated chromospheric activity levels and performed age estimates through 3 additional independent methods: activity-age relations using the Ca II H $\&$ K and H$\alpha$ lines, and rotation periods estimated from TESS light curves. We identified three candidates that provide a good match to the Sun at $\approx$ 0.5 Gyr (HD 13531 and HD 61033) and subgiant (HD 148577) stages. Moreover, HD 197210 could be of interest when studying the Sun at $\approx$ 2 Gyr, when the Earth's atmosphere started having a significant amount of oxygen. Our selection method was successful and we were able to identify stars similar to the Sun at different evolutionary stages, which is essential for future research in the search of exoplanets and understand habitability, especially with the advent of the next generation of exoplanet-hunting instruments.