The Chemical Homogeneity of Sun-like Stars in the Solar Neighborhood

Megan Bedell, Jacob L. Bean, Jorge Meléndez, Lorenzo Spina, Ivan Ramirez, Martin Asplund, Alan Alves-Brito, Leonardo Dos Santos, Stefan Dreizler, David Yong, Talawanda Monroe, Luca Casagrande

Research output: Contribution to journalArticleResearchpeer-review

36 Citations (Scopus)

Abstract

The compositions of stars are a critical diagnostic tool for many topics in astronomy such as the evolution of our Galaxy, the formation of planets, and the uniqueness of the Sun. Previous spectroscopic measurements indicate a large intrinsic variation in the elemental abundance patterns of stars with similar overall metal content. However, systematic errors arising from inaccuracies in stellar models are known to be a limiting factor in such studies, and thus it is uncertain to what extent the observed diversity of stellar abundance patterns is real. Here we report the abundances of 30 elements with precisions of 2% for 79 Sun-like stars within 100 pc. Systematic errors are minimized in this study by focusing on solar twin stars and performing a line-by-line differential analysis using high-resolution, high-signal-to-noise spectra. We resolve [X/Fe] abundance trends in galactic chemical evolution at precisions of 10-3 dex Gyr-1 and reveal that stars with similar ages and metallicities have nearly identical abundance patterns. Contrary to previous results, we find that the ratios of carbon-to-oxygen and magnesium-to-silicon in solar-metallicity stars are homogeneous to within 10% throughout the solar neighborhood, implying that exoplanets may exhibit much less compositional diversity than previously thought. Finally, we demonstrate that the Sun has a subtle deficiency in refractory material relative to >80% of solar twins (at 2σ confidence), suggesting a possible signpost for planetary systems like our own.

Original languageEnglish
Article number68
Number of pages13
JournalThe Astrophysical Journal
Volume865
Issue number1
DOIs
Publication statusPublished - 20 Sep 2018

Keywords

  • planets and satellites: general
  • stars: abundances
  • stars: solar-type
  • Sun: abundances
  • techniques: spectroscopic

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