What are little worlds made of? Stellar abundances and the building blocks of planets

Abstract

If the photospheres of solar-type stars represent the composition of circumstellar disks from which any planets formed, spectroscopic determinations of stellar elemental abundances offer information on the composition of those planets, including smaller, rocky planets. In particular, the C/O ratio is proposed to be a key determinant of the composition of solids that condense from disk gas and are incorporated into planets. Also, planets may leave chemical signatures on the photospheres of their host stars by sequestering heavy elements, or by being accreted by the stars. The presence, absence, and composition of planets could be revealed by small differences in the relative abundances between stars. I critically examine these scenarios and show that (i) a model of Galactic chemical evolution predicts that the C/O ratio is expected to be close to the solar value and vary little between dwarf stars in the solar neighborhood; (ii) spectroscopic surveys of M dwarf stars limit the occurrence of stars with C/O $\gtrsim 1$ to $<10^{-3}$; and (iii) planetesimal chemistry will be controlled by the composition of oxygen-rich dust inherited from the molecular cloud and processed in a dust-rich environment, not a gas with the stellar composition. A second generation of more reduced planetesimals could be produced by re-equilibration of some material with dust-depleted gas. Finally, I discuss how minor differences in relative abundances between stars that correlate with condensation temperature can be explained by dust-gas segregation, perhaps in circumstellar disks, rather than planet formation.

arXiv commentApJ, in press

References in corpus (86)

• The chemical composition of the Sun
• Interstellar Dust Grains
• The CO-to-H2 Conversion Factor
• The Neutral Atomic Phases of the ISM in the Galaxy
• The effects of snowlines on C/O in planetary atmospheres
• Spectroscopic [Fe/H] for 98 extra-solar planet-host stars: Exploring the probability of planet formation
• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• Galactic Chemical Evolution: Hydrogen Through Zinc
• Galactic chemical evolution: Carbon through Zinc
• Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere
• Prevalence of Earth-size planets orbiting Sun-like stars
• The Mass Dependence Between Protoplanetary Disks and their Stellar Hosts
• Updated stellar yields from Asymptotic Giant Branch models
• Masses, Radii, and Orbits of Small Kepler Planets: The Transition from Gaseous to Rocky Planets
• Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
• The peculiar solar composition and its possible relation to planet formation
• The evolution of amorphous hydrocarbons in the ISM: dust modelling from a new vantage point
• A Survey and Analysis of Spitzer Infrared Spectrograph Spectra of T Tauri Stars in Taurus
• The Evolution of Isotope Ratios in the Milky Way Galaxy
• Star Formation Efficiencies and Lifetimes of Giant Molecular Clouds in the Milky Way
• The Geneva-Copenhagen Survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk
• Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs
• M-Subdwarfs: Spectroscopic Classification and the Metallicity Scale
• Toward a Unification of Star Formation Rate Determinations in the Milky Way and Other Galaxies
• High C/O Ratio and Weak Thermal Inversion in the Very Hot Atmosphere of Exoplanet WASP-12b
• On the theory of disc photoevaporation
• The Sloan Digital Sky Survey Data Release 7 Spectroscopic M Dwarf Catalog I: Data
• The Compositional Diversity of Extrasolar Terrestrial Planets: I. In-Situ Simulations
• Trumpeting M Dwarfs with CONCH-SHELL: a Catalog of Nearby Cool Host-Stars for Habitable ExopLanets and Life
• A Systematic Retrieval Analysis of Secondary Eclipse Spectra II: A Uniform Analysis of Eight Planets and Their C to O Ratios
• Revised metallicity classes for low-mass stars: dwarfs (dM), subdwarfs (sdM), extreme subdwarfs (esdM), and ultra subdwarfs (usdM)
• Dust Growth and Settling in Protoplanetary Disks and Disk Spectral Energy Distributions. I. Laminar Disks
• Chemical Clues on the Formation of Planetary Systems: C/O vs Mg/Si for HARPS GTO Sample
• Super and Massive AGB Stars: II - Nucleosynthesis and Yields - Z=0.02, 0.008 and 0.004
• The Evolution of C/O in Dwarf Galaxies from HST Fos Observations
• A Statistical Reconstruction of the Planet Population Around Kepler Solar-Type Stars
• A simple model for the evolution of disc galaxies: The Milky Way
• Evidence for Disk Photoevaporation Driven by the Central Star
• Interstellar Dust Inside and Outside the Heliosphere
• Modal abundances of CAIs: Implications for bulk chondrite element abundances and fractionations
• Re-Evaluating WASP-12b: Strong Emission at 2.315 micron, Deeper Occultations, and an Isothermal Atmosphere
• Probing the extreme planetary atmosphere of WASP-12b
• Searching for the signatures of terrestrial planets in F-, G-type main-sequence stars
• Deciphering the Atmospheric Composition of WASP-12b: A Comprehensive Analysis of its Dayside Emission
• Carbon and oxygen abundances from recombination lines in low-metallicity star-forming galaxies. Implications for chemical evolution
• C, S, Zn and Cu abundances in planet-harbouring stars
• The C/O ratio at low metallicity: constraints on early chemical evolution from observations of Galactic halo stars
• Abundances and possible diffusion of elements in M67 stars
• On the Carbon-to-Oxygen Ratio Measurement in Nearby Sunlike Stars: Implications for Planet Formation and the Determination of Stellar Abundances
• Silicon and Nickel Enrichment in Planet-Host Stars: Observations and Implications for the Core-Accretion Theory of Planet Formation
• Three carbon-enhanced metal-poor dwarf stars from the SDSS - Chemical abundances from CO^5BOLD 3D hydrodynamical model atmospheres
• Features in the Broadband Eclipse Spectra of Exoplanets: Signal or Noise?
• Oxygen abundances in planet-harbouring stars. Comparison of different abundance indicators
• C/O Ratios of Stars with Transiting Hot Jupiter Exoplanets
• A possible signature of terrestrial planet formation in the chemical composition of solar analogs
• Chemistry in an Evolving Protoplanetary Disk: Effects on Terrestrial Planet Composition
• Carbon and Oxygen in Nearby Stars: Keys to Protoplanetary Disk Chemistry
• High precision abundances in the 16 Cyg binary system: a signature of the rocky core in the giant planet
• A high precision chemical abundance analysis of the HAT-P-1 stellar binary: constraints on planet formation
• Dust Coagulation and Settling in Layered Protoplanetary Disks
• Innocent Bystanders: Carbon Stars from the Sloan Digital Sky Survey
• Cool Subdwarf Investigations (CSI) I: New Thoughts for the Spectral Types of K and M Subdwarfs
• The Evolution of Carbon and Oxygen in the Bulge and Disk of the Milky Way
• Faint High-Latitude Carbon Stars Discovered by the Sloan Digital Sky Survey: An Initial Catalog
• The Compositional Diversity of Extrasolar Terrestrial Planets: II. Migration Simulations
• `Tail-end' Bondi-Hoyle accretion in young star clusters: Implications for disks, planets, and stars
• The carbon-to-oxygen ratio in stars with planets
• Carbon and Oxygen Abundances in Cool Metal-rich Exoplanet Hosts: A Case Study of the C/O Ratio of 55 Cancri
• On the origin of elemental abundances in the terrestrial planets
• Dust Size Growth and Settling in a Protoplanetary Disk
• A high resolution spectroscopic atlas of M subdwarfs - Effective temperature and metallicity
• On the likelihood of supernova enrichment of protoplanetary disks
• Radial Transport in the Solar Nebula: Implications for Moderately Volatile Element Depletions in Chondritic Meteorites
• M dwarf catalog of LAMOST pilot survey
• The origin of carbon: Low-mass stars and an evolving, initially top-heavy IMF?
• Carbon and Oxygen Abundances in the Hot Jupiter Exoplanet Host Star XO-2N and its Binary Companion
• Can We Trust the Dust? Evidence of Dust Segregation in Molecular Clouds
• An Introduction to Galactic Chemical Evolution
• Revisiting Acceleration of Charged Grains in Magnetohydrodynamic Turbulence
• The Homogeneity of Interstellar Krypton in the Galactic Disk
• Forever Young: High Chromospheric Activity in M subdwarfs
• Evolution of the Abundance of CO, O2, and Dust in the Early Universe
• Nonresonant Grain Acceleration in MHD Turbulence
• Enrichment of the dust-to-gas mass ratio in Bondi/Jeans accretion/cloud systems due to unequal changes in dust and gas incoming velocities
• Spectropolarimetric Constraints on the Nature of Interstellar Grains
• Possible Overionization of C II, N II, and O II Ions in the Atmospheres of Early B- and Late O-Type Stars

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• Sun-like stars unlike the Sun: Clues for chemical anomalies of cool stars
• Spatially resolving the chemical composition of the planet building blocks
• The Missing Link: Testing Galactic Chemical Evolution Models with the First Multi-Isotopic Abundances in Solar Twin Stars
• The GAPS Programme at TNG. LIII. New insights on the peculiar XO-2 system