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

(abridged) A detailed study of the blue supergiant UIT005 (B2-2.5Ia+) in M33is presented. The results of our quantitative spectral analysis indicate thatthe star is a very luminous, log(L/Lsun)~5.9 dex, and massive, M~50 Msun,object, showing a very high nitrogen-to-oxygen ratio in its surface (N/O~8, bymass). Based on the derived Mg and Si abundances, we argue that this high N/Oratio cannot be the result of an initial low O content due to its location onthe disk of M33, known to present a steep metallicity gradient. In combinationwith the He abundance, the most plausible interpretation is that UIT005 is inan advanced stage of evolution, showing in its surface N enrichment and Odepletion resulting from mixing with CNO processed material from the stellarinterior. A comparison with the predictions of current stellar evolutionarymodels indicates that there are significant discrepancies, in particular withregard to the degree of chemical processing, with the models predicting a muchlower degree of O depletion than observed. At the same time, the mass-loss ratederived in our analysis is an order of magnitude lower than the valuesconsidered in the evolutionary calculations. Based on a study of thesurrounding stellar population and the nearby cluster NGC588, using WFPC2photometry, we suggest that UIT005 could be in fact a runaway star from thiscluster.

Blue luminous stars in nearby galaxies - UIT005: a possible link to the luminous blue variable stage