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Radial abundance gradients in the outer Galactic disk as traced by main-sequence OB stars
- Source :
- Astronomy & Astrophysics. 625:A120
- Publication Year :
- 2019
- Publisher :
- EDP Sciences, 2019.
-
Abstract
- Using a sample of 31 main-sequence OB stars located between galactocentric distances 8.4 - 15.6 kpc, we aim to probe the present-day radial abundance gradients of the Galactic disk. The analysis is based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan Clay 6.5-m telescope on Las Campanas. We used a non-NLTE analysis in a self-consistent semi-automatic routine based on TLUSTY and SYNSPEC to determine atmospheric parameters and chemical abundances. Stellar parameters (effective temperature, surface gravity, projected rotational velocity, microturbulence, and macroturbulence) and silicon and oxygen abundances are presented for 28 stars located beyond 9 kpc from the Galactic centre plus three stars in the solar neighborhood. The stars of our sample are mostly on the main-sequence, with effective temperatures between 20800 - 31300 K, and surface gravities between 3.23 - 4.45 dex. The radial oxygen and silicon abundance gradients are negative and have slopes of -0.07 dex/kpc and -0.09 dex/kpc, respectively, in the region $8.4 \leq R_G \leq 15.6$\,kpc. The obtained gradients are compatible with the present-day oxygen and silicon abundances measured in the solar neighborhood and are consistent with radial metallicity gradients predicted by chemodynamical models of Galaxy Evolution for a subsample of young stars located close to the Galactic plane.<br />Accepted for publication in the A&A
- Subjects :
- Stellar population
Astrophysics::High Energy Astrophysical Phenomena
Metallicity
Milky Way
FOS: Physical sciences
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
01 natural sciences
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
Disc
010303 astronomy & astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
Astrophysics::Galaxy Astrophysics
Physics
Spiral galaxy
010308 nuclear & particles physics
Galactic Center
Astronomy and Astrophysics
Galactic plane
Astrophysics - Astrophysics of Galaxies
Stars
Astrophysics - Solar and Stellar Astrophysics
13. Climate action
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
Astrophysics::Earth and Planetary Astrophysics
Subjects
Details
- ISSN :
- 14320746 and 00046361
- Volume :
- 625
- Database :
- OpenAIRE
- Journal :
- Astronomy & Astrophysics
- Accession number :
- edsair.doi.dedup.....c11cbb0bc31f79cc9b0ca1fb64d59e9f