Revisiting the Li abundances of Stars with and without Detected Planets from the High Resolution Spectroscopy

TL;DR

This study compares lithium abundances in stars with and without detected planets, finding no significant difference, and emphasizes the importance of non-LTE corrections for accurate Li measurements.

Contribution

It provides a large, homogeneous analysis of Li abundances in planet-host and isolated stars, clarifying the impact of planets on stellar Li depletion.

Findings

Li distributions are similar in both star groups

Presence of Kepler-like planets does not significantly affect Li depletion

Non-LTE corrections are crucial for stars with high Li abundance

Abstract

Whether the presence of planets affects the lithium (Li) abundance of their host stars is still an open question. To investigate the difference of the Li abundance between planet-host stars (HS) and isolated stars (IS) with no detected planets, we analyze a large sample of stars with temperatures ranging from 4600 to 6600 K and metallicity ranging from -0.55 to +0.50. The sample consists of 279 HS whose spectra were taken from the California-Kepler Survey (CKS), which followed up planets detected by Kepler, and 171 IS whose spectra were taken from the Keck archive. The non-local thermodynamic equilibrium (non-LTE) effects were taken into consideration. It is found that the distribution of Li abundances in both the HS and IS groups are generally consistent with each other. This suggests that the presence of Kepler-like planets does not have a significant impact on Li depletion. We also found that the non-LTE corrections can not be neglected for stars with A(Li) over ~ 2.5 dex.