The Gaia-ESO Survey: radial distribution of abundances in the Galactic disc from open clusters and young-field stars
Ffi, A Chie
ASTRONOMY & ASTROPHYSICS
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Magrini, L., Randich, S., Kordopatis, G., Prantzos, N., Romano, D., Ffi, A. C., Limongi, M., et al. (2017). The Gaia-ESO Survey: radial distribution of abundances in the Galactic disc from open clusters and young-field stars. ASTRONOMY & ASTROPHYSICS, 603 (ARTN A2) https://doi.org/10.1051/0004-6361/201630294
The spatial distribution of elemental abundances in the disc of our Galaxy gives insights both on its assembly process and subsequent evolution, and on the stellar nucleogenesis of the different elements. Gradients can be traced using several types of objects as, for instance, (young and old) stars, open clusters, HII regions, planetary nebulae. We aim at tracing the radial distributions of abundances of elements produced through different nucleosynthetic channels -the alpha-elements O, Mg, Si, Ca and Ti, and the iron-peak elements Fe, Cr, Ni and Sc - by using the Gaia-ESO idr4 results of open clusters and young field stars. From the UVES spectra of member stars, we determine the average composition of clusters with ages >0.1 Gyr. We derive statistical ages and distances of field stars. We trace the abundance gradients using the cluster and field populations and we compare them with a chemo-dynamical Galactic evolutionary model. Results. The adopted chemo-dynamical model, with the new generation of metallicity-dependent stellar yields for massive stars, is able to reproduce the observed spatial distributions of abundance ratios, in particular the abundance ratios of [O/Fe] and [Mg/Fe] in the inner disc (5 kpc<RGC <7 kpc), with their differences, that were usually poorly explained by chemical evolution models. Often, oxygen and magnesium are considered as equivalent in tracing alpha-element abundances and in deducing, e.g., the formation time-scales of different Galactic stellar populations. In addition, often [alpha/Fe] is computed combining several alpha-elements. Our results indicate, as expected, a complex and diverse nucleosynthesis of the various alpha-elements, in particular in the high metallicity regimes, pointing towards a different origin of these elements and highlighting the risk of considering them as a single class with common features.
Galaxy: abundances, open clusters and associations: general
This work was partially supported by the Gaia Research for European Astronomy Training (GREAT-ITN) Marie Curie network, funded through the European Union Seventh Framework Programme [FP7/2007-2013] under grant agreement n. 264895. This work was partly supported support through the European Research Council grant 320360: The Gaia-ESO Milky Way Survey G.T. and A.D. acknowledge support by the Research Council of Lithuania (MIP- 082 / 2015). This research has been partially supported by the National Institute for Astrophysics (INAF) through the grant PRIN-2014 ("Transient Universe, unveiling new types of stellar explosions with PESSTO"). F.J.E. acknowledges financial support from the Spacetec-CM project (S2013/ICE-2822). S.F. and T.B. are supported by the project grant "The New Milky Way" from the Knut and Alice Wallenberg Foundation. Support for SD was provided by the Chile’s Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS.
European Commission (264895)
European Research Council (320360)
External DOI: https://doi.org/10.1051/0004-6361/201630294
This record's URL: https://www.repository.cam.ac.uk/handle/1810/264379