skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Solar Elemental Abundances
olar elemental abundances, or solar system elemental abundances refer to the complement of chemical elements in the entire solar system. The sun contains more than 99-percent of the mass in the solar system and therefore the composition of the sun is a good proxy for the composition of the overall solar system. The solar system composition can be taken as the overall composition of the molecular cloud within the interstellar medium from which the solar system formed 4.567 billion years ago. Active research areas in astronomy and cosmochemistry model collapse of a molecular cloud of solar composition into a star with a planetary system, and the physical and chemical fractionation of the elements during planetary formation and differentiation. The solar system composition is the initial composition from which all solar system objects (the sun, terrestrial planets, gas giant planets, planetary satellites and moons, asteroids, Kuiper-belt objects, and comets) were derived. Other dwarf stars (with hydrostatic Hydrogen-burning in their cores) like our Sun (type G2V dwarf star) within the solar neighborhood have compositions similar to our Sun and the solar system composition. In general, differential comparisons of stellar compositions provide insights about stellar evolution as functions of stellar mass and age, and ongoing nucleosynthesis; but also about galactic chemical evolution when elemental compositions of stellar populations across our Milky Way Galaxy is considered. Comparisons to solar composition can reveal element destruction (e.g., Li) in the sun and in other dwarf stars. The comparisons also show element production of e.g., C, N, O, and the heavy elements made by the s-process in low- to intermediate mass stars (3-7 solar masses) after these evolved from their dwarf-star stage into red giant stars (where hydrogen and helium burning can occur in shells around their cores). The solar system abundances are and have been a critical test composition for nucleosynthesis models and models of Galactic chemical evolution, which aim ultimately to track the production of the elements heavier than hydrogen and helium in the generation of stars that came forth after the Big Bang 13.4 billion years ago. Article at: https://oxfordre.com/planetaryscience/view/10.1093/acrefore/9780190647926.001.0001/acrefore-9780190647926-e-145  more » « less
Award ID(s):
1517541
PAR ID:
10642794
Author(s) / Creator(s):
Publisher / Repository:
Online Oxford Research Encyclopedia of Planetary Science. Oxford University Press 2020
Date Published:
Subject(s) / Keyword(s):
Abundances solar system sun photosphere solar wind meteorites chondrites elements isotopes nuclides history
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; (, Monthly Notices of the Royal Astronomical Society)
    null (Ed.)
    ABSTRACT Planets and stars ultimately form out of the collapse of the same cloud of gas. Whilst planets, and planetary bodies, readily loose volatiles, a common hypothesis is that they retain the same refractory composition as their host star. This is true within the Solar system. The refractory composition of chondritic meteorites, Earth, and other rocky planetary bodies are consistent with solar, within the observational errors. This work aims to investigate whether this hypothesis holds for exoplanetary systems. If true, the internal structure of observed rocky exoplanets can be better constrained using their host star abundances. In this paper, we analyse the abundances of the K-dwarf, G200-40, and compare them to its polluted white dwarf companion, WD 1425+540. The white dwarf has accreted planetary material, most probably a Kuiper belt-like object, from an outer planetary system surviving the star’s evolution to the white dwarf phase. Given that binary pairs are chemically homogeneous, we use the binary companion, G200-40, as a proxy for the composition of the progenitor to WD 1425+540. We show that the elemental abundances of the companion star and the planetary material accreted by WD 1425+540 are consistent with the hypothesis that planet and host-stars have the same true abundances, taking into account the observational errors. 
    more » « less
  2. ; ; ; ; ; ; ; ; ; ; et al (, Monthly Notices of the Royal Astronomical Society)
    ABSTRACT Theoretical physical-chemical models for the formation of planetary systems depend on data quality for the Sun’s composition, that of stars in the solar neighbourhood, and of the estimated ’pristine’ compositions for stellar systems. The effective scatter and the observational uncertainties of elements within a few hundred parsecs from the Sun, even for the most abundant metals like carbon, oxygen and silicon, are still controversial. Here we analyse the stellar production and the chemical evolution of key elements that underpin the formation of rocky (C, O, Mg, Si) and gas/ice giant planets (C, N, O, S). We calculate 198 galactic chemical evolution (GCE) models of the solar neighbourhood to analyse the impact of different sets of stellar yields, of the upper mass limit for massive stars contributing to GCE (Mup) and of supernovae from massive-star progenitors which do not eject the bulk of the iron-peak elements (faint supernovae). Even considering the GCE variation produced via different sets of stellar yields, the observed dispersion of elements reported for stars in the Milky Way (MW) disc is not reproduced. Among others, the observed range of super-solar [Mg/Si] ratios, sub-solar [S/N], and the dispersion of up to 0.5 dex for [S/Si] challenge our models. The impact of varying Mup depends on the adopted supernova yields. Thus, observations do not provide a constraint on the Mup parametrization. When including the impact of faint supernova models in GCE calculations, elemental ratios vary by up to 0.1–0.2 dex in the MW disc; this modification better reproduces observations. 
    more » « less
  3. ; ; ; ; ; (, The Astrophysical Journal)
    Abstract Chemical anomalies in planet-hosting stars (PHSs) are studied in order to assess how the planetary nature and multiplicity affect the atmospheric chemical abundances of their host stars. We employ APOGEE DR17 to select thin-disk stars of the Milky Way, and crossmatch them with the Kepler Input Catalog to identify confirmed PHSs, which results in 227 PHSs with available chemical abundance ratios for six refractory elements. We also examine an ensemble of stars without planet signals, which are equivalent to the selected PHSs in terms of evolutionary stage and stellar parameters, to correct for Galactic chemical evolution effects, and derive the abundance gradient of refractory elements over the condensation temperature for the PHSs. Using the Galactic chemical evolution corrected abundances, we find that our PHSs do not show a significant difference in abundance slope from the stars without planets. However, when we examine the trends of the refractory elements of PHSs, based on the total number of their planets and their planet types, we find that the PHSs with giant planets are more depleted in refractory elements than those with rocky planets. Among the PHSs with rocky planets, the refractory depletion trends are potentially correlated with the terrestrial planets’ radii and multiplicity. In the cases of PHSs with giant planets, sub-Jovian PHSs demonstrate more depleted refractory trends than stars hosting Jovian-mass planets, raising questions on different planetary formation processes for Neptune-like and Jupiter-like planets. 
    more » « less
  4. ; ; ; ; ; ; ; ; ; ; et al (, The Astrophysical Journal)
    Abstract We present observations and analyses of eight white dwarf stars (WDs) that have accreted rocky material from their surrounding planetary systems. The spectra of these helium-atmosphere WDs contain detectable optical lines of all four major rock-forming elements (O, Mg, Si, and Fe). This work increases the sample of oxygen-bearing WDs with parent body composition analyses by roughly 33%. To first order, the parent bodies that have been accreted by the eight WDs are similar to those of chondritic meteorites in relative elemental abundances and oxidation states. Seventy-five percent of the WDs in this study have observed oxygen excesses implying volatiles in the parent bodies with abundances similar to those of chondritic meteorites. Three WDs have oxidation states that imply more reduced material than found in CI chondrites, indicating the possible detection of Mercury-like parent bodies, but are less constrained. These results contribute to the recurring conclusion that extrasolar rocky bodies closely resemble those in our solar system, and do not, as a whole, yield unusual or unique compositions. 
    more » « less
  5. ; ; ; ; ; ; (, The European Physical Journal A)
    Abstract Analysis of bulk meteorite compositions has revealed small isotopic variations due to the presence of material (e.g., stardust) that preserved the signature of nuclear reactions occurring in specific stellar sites. The interpretation of such anomalies provides evidence for the environment of the birth of the Sun, its accretion process, the evolution of the solar proto-planetary disk, and the formation of the planets. A crucial element of such interpretation is the comparison of the observed anomalies to predictions from models of stellar nucleosynthesis. To date, however, this comparison has been limited to a handful of model predictions. This is mostly because the calculated stellar abundances need to be transformed into a specific representation, which nuclear astrophysicists and stellar nucleosynthesis researchers are not familiar with. Here, we show in detail that this representation is needed to account for mass fractionation effects in meteorite data that can be generated both in nature and during instrumental analysis. We explain the required internal normalisation to a selected isotopic ratio, describe the motivations behind such representation more widely, and provide the tools to perform the calculations. Then, we present some examples considering two elements produced by the slow neutron-capture ( s ) process: Sr and Mo. We show which specific representations for the Sr isotopic composition calculated by s -process models better disentangle the nucleosynthetic signatures from stars of different metallicity. For Mo, the comparison between data and models is improved due to a recent re-analysis of the $$^{95}$$ 95 Mo neutron-capture cross section. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email