English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present C and O abundances in the Magellanic Clouds derived from deepspectra of HII regions. The data have been taken with the Ultraviolet-VisualEchelle Spectrograph at the 8.2-m VLT. The sample comprises 5 HII regions inthe Large Magellanic Cloud (LMC) and 4 in the Small Magellanic Cloud (SMC). Wemeasure pure recombination lines (RLs) of CII and OII in all the objects,permitting to derive the abundance discrepancy factors (ADFs) for O^2+, as wellas their O/H, C/H and C/O ratios. We compare the ADFs with those of other HIIregions in different galaxies. The results suggest a possible metallicitydependence of the ADF for the low-metallicity objects, but more uncertain forhigh-metallicity objects. We compare nebular and B-type stellar abundances andwe find that the stellar abundances agree better with the nebular ones derivedfrom collisionally excited lines (CELs). Comparing these results with othergalaxies we observe that stellar abundances seem to agree better with thenebular ones derived from CELs in low-metallicity environments and from RLs inhigh-metallicity environments. The C/H, O/H and C/O ratios show almost flatradial gradients, in contrast with the spiral galaxies where such gradients arenegative. We explore the chemical evolution analysing C/O vs. O/H and comparingwith the results of HII regions in other galaxies. The LMC seems to show asimilar chemical evolution to the external zones of small spiral galaxies andthe SMC behaves as a typical star-forming dwarf galaxy.

Carbon and oxygen in HII regions of the Magellanic Clouds: abundance discrepancy and chemical evolution