Detailed Abundances of Planet-Hosting Open Clusters. The Praesepe (Beehive) Cluster

TL;DR

This study provides a detailed chemical abundance analysis of stars in the Praesepe cluster, including a planet-hosting star, to investigate how planet formation influences stellar compositions and to assess chemical homogeneity within the cluster.

Contribution

It introduces a novel approach to equivalent width measurements and offers the first detailed chemical abundance analysis of Praesepe stars with a focus on planet-hosting effects.

Findings

Praesepe has a mean metallicity of [Fe/H] = +0.21 dex.

Stars in Praesepe are chemically homogeneous with minimal abundance scatter.

The planet-hosting star shows no significant chemical enrichment from planetary accretion.

Abstract

It is not yet fully understood how planet formation affects the properties of host stars, in or out of a cluster; however, abundance trends can help us understand these processes. We present a detailed chemical abundance analysis of six stars in Praesepe, a planet-hosting open cluster. Pr0201 is known to host a close-in (period of 4.4 days) giant planet (mass of 0.54$\rm M_{\rm{J}}$), while the other five cluster members in our sample (Pr0133, Pr0081, Pr0208, Pr0051, and Pr0076) have no detected planets according to RV measurements. Using high-resolution, high signal-to-noise echelle spectra obtained with Keck/HIRES and a novel approach to equivalent width measurements (XSpect-EW), we derived abundances of up to 20 elements spanning a range of condensation temperatures (Tc). We find a mean cluster metallicity of [Fe/H] = +0.21$\pm$0.02 dex, in agreement with most previous determinations. We find most of our elements show a [X/Fe] scatter of $\sim$0.02-0.03 dex and conclude that our stellar sample is chemically homogeneous. The Tc slope for the cluster mean abundances is consistent with zero and none of the stars in our sample exhibit individually a statistically significant Tc slope. Using a planet engulfment model, we find that the planet-host, Pr0201, shows no evidence of significant enrichment in its refractory elements when compared to the cluster mean that would be consistent with a planetary accretion scenario.