The Influence of 10 Unique Chemical Elements in Shaping the Distribution of Kepler Planets

Abstract

The chemical abundances of planet-hosting stars offer a glimpse into the composition of planet-forming environments. To further understand this connection, we make the first ever measurement of the correlation between planet occurrence and chemical abundances for ten different elements (C, Mg, Al, Si, S, K, Ca, Mn, Fe, and Ni). Leveraging data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and Gaia to derive precise stellar parameters (${\sigma }_{R_{\star }}\approx 2.3\%$, ${\sigma }_{M_{\star }}\approx 4.5\%$) for a sample of 1,018 Kepler Objects of Interest, we construct a sample of well-vetted Kepler planets with precisely measured radii (${\sigma }_{R_p}\approx 3.4\%$). After controlling for biases in the Kepler detection pipeline and the selection function of the APOGEE survey, we characterize the relationship between planet occurrence and chemical abundance as the number density of nuclei of each element in a star's photosphere raised to a power, $\beta$. $\beta$ varies by planet type, but is consistent within our uncertainties across all ten elements. For hot planets ($P$ = 1-10 days), an enhancement in any element of 0.1 dex corresponds to an increased occurrence of $\approx$20% for Super-Earths ($R_p=1-1.9R_{\oplus }$) and $\approx$60% for Sub-Neptunes ($R_p=1.9-4R_{\oplus }$). Trends are weaker for warm ($P$ = 10-100 days) planets of all sizes and for all elements, with the potential exception of Sub-Saturns ($R_p=4-8R_{\oplus }$). Finally, we conclude this work with a caution to interpreting trends between planet occurrence and stellar age due to degeneracies caused by Galactic chemical evolution and make predictions for planet occurrence rates in nearby open clusters to facilitate demographics studies of young planetary systems.

Accepted to AJ; 25 Figures; 67 Pages

References in corpus (44)

• Array Programming with NumPy
• The Transiting Exoplanet Survey Satellite
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• The K2 Mission: Characterization and Early results
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes
• APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South
• The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
• A new implementation of the infrared flux method using the 2MASS catalogue
• Three regimes of extrasolar planets inferred from host star metallicities
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs
• A stellar-mass-dependent drop in planet occurrence rates
• Target Selection for the SDSS-IV APOGEE-2 Survey
• Asteroseismology and Gaia: Testing Scaling Relations Using 2200 Kepler Stars with TGAS Parallaxes
• Planetary Candidates Observed by Kepler VI: Planet Sample from Q1-Q16 (47 Months)
• A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes
• Stellar Parameters and Metallicities of Stars Hosting Jovian and Neptunian Mass Planets: A Possible Dependence of Planetary Mass on Metallicity
• The Gaia-Kepler Stellar Properties Catalog. II. Planet Radius Demographics as a Function of Stellar Mass and Age
• The Open Cluster Chemical Abundances and Mapping Survey: IV. Abundances for 128 Open Clusters using SDSS/APOGEE DR16
• The APOGEE Data Release 16 Spectral Line List
• New H-band Stellar Spectral Libraries for the SDSS-III/APOGEE survey
• Close Binary Companions to APOGEE DR16 Stars: 20,000 Binary-star Systems Across the Color-Magnitude Diagram
• Exploring the alpha-enhancement of metal-poor planet-hosting stars. The Kepler and HARPS samples
• A Spectroscopic Analysis of the California-Kepler Survey Sample: I. Stellar Parameters, Planetary Radii and a Slope in the Radius Gap
• A Super-Solar Metallicity For Stars With Hot Rocky Exoplanets
• From planetesimals to planets: volatile molecules
• Zodiacal Exoplanets in Time (ZEIT) VI: a three-planet system in the Hyades cluster including an Earth-sized planet
• Four Sub-Saturns with Dissimilar Densities: Windows into Planetary Cores and Envelopes
• Zodiacal Exoplanets in Time (ZEIT) V: A Uniform Search for Transiting Planets in Young Clusters Observed by K2
• Chemical Abundances of Main-Sequence, Turnoff, Subgiant and red giant Stars from APOGEE spectra II: Atomic Diffusion in M67 Stars
• Bayesian analysis of interiors of HD 219134b, Kepler-10b, Kepler-93b, CoRoT-7b, 55 Cnc e, and HD 97658b using stellar abundance proxies
• Testing the radius scaling relation with $Gaia$ DR2 in the $Kepler$ field
• Sodium and Oxygen Abundances in the Open Cluster NGC 6791 from APOGEE H-Band Spectroscopy
• Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program IV. Carbon and C/O ratios for Galactic stellar populations and planet hosts
• A Continuum of Planet Formation Between 1 and 4 Earth Radii
• Connecting substellar and stellar formation. The role of the host star's metallicity
• Elemental Abundances of Kepler Objects of Interest in APOGEE. I. Two Distinct Orbital Period Regimes Inferred from Host Star Iron Abundances
• Chemical abundances of 1111 FGK stars from the HARPS-GTO planet search sample. III. Sulfur
• Planets Around Low-Mass Stars (PALMS). V. Age-Dating Low-Mass Companions to Members and Interlopers of Young Moving Groups
• The Metallicity-Period-Mass Diagram of low-mass exoplanets
• The APOGEE Spectroscopic Survey of Kepler Planet Hosts: Feasibility, Efficiency, and First Results
• The velocity ellipsoid in the Galactic disc using Gaia DR1
• Reliability Correction is Key for Robust Kepler Occurrence Rates
• A Spectroscopic Analysis of the California-Kepler Survey Sample: II. Correlations of Stellar Metallicities with Planetary Architectures

Cited by in corpus (9)

• Creating the Radius Gap without Mass Loss
• Scaling K2. VI. Reduced Small Planet Occurrence in High Galactic Amplitude Stars
• Searching for Giant Exoplanets around M-dwarf Stars (GEMS) I: Survey Motivation
• Galactic chemical evolution of exoplanet host stars: Are high-mass planetary systems young?
• A High-Resolution Spectroscopic Survey of Directly Imaged Companion Hosts: I. Determination of diagnostic stellar abundances for planet formation and composition
• A comprehensive study of the relations between the properties of planetary systems and the chemical compositions of their host stars
• On the Dynamical Erasure of Initial Conditions in Multi-Planetary Systems
• Characterization of low-mass companions to $\text{Kepler}$ objects of interest observed with APOGEE-N
• The Multiband Imaging Survey for High-Alpha PlanetS (MISHAPS) I: Preliminary Constraints on the Occurrence Rate of Hot Jupiters in 47 Tucanae