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

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 this process. 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 M J ), while the other five cluster members in our sample (Pr0133, Pr0081, Pr0208, Pr0051, and Pr0076) have no detected planets according to measurements of radial velocity. Using high-resolution echelle spectra with high signal-to-noise ratio obtained with Keck/HIRES and a novel approach to measurements of equivalent width (XSpect-EW), we derived abundances of up to 20 elements spanning a range of condensation temperatures ( T C ). We find a mean cluster metallicity of [Fe/H] = +0.21 ± 0.02 dex, in agreement with most previous determinations. We find most of our elements show an [X/Fe] scatter of ∼0.02–0.03 dex and conclude that our stellar sample is chemically homogeneous. The T C slope for the cluster mean abundances is consistent with zero and none of the stars in our sample exhibit individually a statistically significant T C 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.