Chemical Abundances of Main-sequence, Turnoff, Subgiant, and Red Giant Stars from APOGEE Spectra. II. Atomic Diffusion in M67 Stars

Diogo Souto, C. Allende Prieto, Katia Cunha, Marc Pinsonneault, Verne V. Smith, R. Garcia-Dias, Jo Bovy, D. A. Garcia-Hernández, Jon Holtzman, J. A. Johnson, Henrik Jönsson, Steve R. Majewski, Matthew Shetrone, Jennifer Sobeck, Olga Zamora, Kaike Pan, Christian Nitschelm

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Chemical abundances for 15 elements (C, N, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Ni) are presented for 83 stellar members of the 4 Gyr old solar-metallicity open cluster M67. The sample contains stars spanning a wide range of evolutionary phases, from G dwarfs to red clump stars. The abundances were derived from near-IR (λ1.5-1.7 μm) high-resolution spectra (R ,F= ,F22,500) from the SDSS-IV/Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. A 1D local thermodynamic equilibrium abundance analysis was carried out using the APOGEE synthetic spectral libraries, via χ 2 minimization of the synthetic and observed spectra with the qASPCAP code. We found significant abundance differences (∼0.05-0.30 dex) between the M67 member stars as a function of the stellar mass (or position on the Hertzsprung-Russell diagram), where the abundance patterns exhibit a general depletion (in [X/H]) in stars at the main-sequence turnoff. The amount of the depletion is different for different elements. We find that atomic diffusion models provide, in general, good agreement with the abundance trends for most chemical species, supporting recent studies indicating that measurable atomic diffusion operates in M67 stars.

Original languageEnglish (US)
Article number97
JournalAstrophysical Journal
Volume874
Issue number1
DOIs
StatePublished - Mar 20 2019
Externally publishedYes

Keywords

  • diffusion
  • infrared: stars
  • open clusters and associations: general
  • stars: abundances

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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