HIP 56948: A Solar Twin With a Low Lithium Abundance

TL;DR

HIP 56948 is identified as the best solar twin known, closely matching the Sun in stellar parameters, chemical composition, and low lithium abundance, making it a prime candidate for studying planetary habitability and SETI.

Contribution

The paper reports the discovery of HIP 56948 as the most similar solar twin with a low lithium abundance, refining our understanding of solar analogs and their potential for hosting life.

Findings

HIP 56948 has stellar parameters identical to the Sun within uncertainties.

HIP 56948 exhibits a low lithium abundance similar to the Sun.

HIP 56948 lacks hot Jupiters, like the Sun.

Abstract

For more than a decade, 18 Sco (HD 146233) has been considered the star that most closely resembles the Sun, even though significant differences such as its Li content, which is about three times solar, exist. Using high resolution, high S/N spectra obtained at McDonald Observatory, we show that the stars HIP 56948 and HIP 73815 are very similar to the Sun in both stellar parameters and chemical composition, including a low Li abundance, which was previously thought to be peculiar in the Sun. HIP 56948, in particular, has stellar parameters identical to solar within the observational uncertainties, being thus the best solar twin known to date. HIP 56948 is also similar to the Sun in its lack of hot Jupiters. Considering the age of this star (1+/-1 Gyr older than the Sun) and its location and orbit around the Galaxy, if terrestrial planets exist around it, they may have had enough time to develop complex life, making it a prime target for SETI.