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Table · dataset · 2018

Equivalent widths of 7 stars in NGC 6705

Listed in IVOA Registry (Virtual Observatory)

The stellar [{alpha}/Fe] abundance is sometimes used as a proxy for stellar age, following standard chemical evolution models for the Galaxy, as seen by different observational results.

Description

In this work we show that the Open Cluster NGC6705/M11 has a significant {alpha}-enhancement [{alpha}/Fe]>0.1dex, despite its young age (~300Myr), challenging the current paradigm.}{We use high resolution (R$>65,000$) high signal-to-noise (~70) spectra of 8 Red Clump stars, acquired within the OCCASO survey.

We determine very accurate chemical abundances of several {alpha} elements, using an equivalent width methodology (Si, Ca and Ti), and spectral synthesis fits (Mg and O). We obtain [Si/Fe]=0.13+/-0.05, [Mg/Fe]=0.14+/-0.07, [O/Fe]=0.17+/-0.07, [Ca/Fe]=0.06+/-0.05 and [Ti/Fe]=0.03+/-0.03. Our results place these cluster within the group of young [{alpha}/Fe]-enhanced field stars recently found by several authors in the literature.

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The ages of our stars have an uncertainty of around 50Myr, much more precise than for field stars. By integrating the cluster's orbit in several non-axisymmetric Galactic potentials, we establish the M11's most likely birth radius to lie between 6.8-7.5kpc from the Galactic center, not far from its current position. With the robust Open Cluster age scale, our results prove that a moderate [{alpha}/Fe]-enhancement is no guarantee for a star to be old, and that not all {alpha}-enhanced stars can be explained with an evolved blue straggler scenario.

Based on our orbit calculations, we further argue against a Galactic bar origin of M11.

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Documentation and papers

Catalogue records · 2

Topics

Provenance · 1 source records, 7 field assertions
SourceKeyLast seenRaw
IVOA Registry (Virtual Observatory)ivo://cds.vizier/j/a+a/610/a6614 d agoJSON v1
FieldAssertionExtractorEvidence
access_levelsource · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[field].local:field:astronomymapping · IVOA Registryconnector:ivoa_registry@1.0.0
descriptionsource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_description
license_textsource · IVOA Registryconnector:ivoa_registry@1.0.0
publication_datesource · IVOA Registryconnector:ivoa_registry@1.0.0
titlesource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_title
updated_datesource · IVOA Registryconnector:ivoa_registry@1.0.0