Revising the evolutionary stage of HD 163899: the effects of convective overshooting and rotation

TL;DR

This paper re-evaluates the evolutionary stage of the B-type supergiant HD 163899, suggesting it is likely still on the main sequence, influenced by convective overshooting and rotation effects, based on new observational data and spectral analysis.

Contribution

It introduces revised models considering convective overshooting and rotation, providing a new interpretation of HD 163899's evolutionary status as a nitrogen-rich main-sequence star.

Findings

HD 163899 is likely still on the main sequence.

Rotational mixing explains nitrogen overabundance.

More massive models better fit the observations.

Abstract

We revise the evolutionary status of the B-type supergiant HD\,163899 based on the new determinations of the mass-luminosity ratio, effective temperature and rotational velocity as well as on the interpretation of the oscillation spectrum of the star. The observed value of the nitrogen-to-carbon abundance fixes the value of the rotation rate of the star. Now, more massive models are strongly preferred than those previously considered and it is very likely that the star is still in the main sequence stage. The rotationally induced mixing manifests as the nitrogen overabundance in the atmosphere, which agrees with our analysis of the HARPS spectra. Thus, HD\,163899 belongs probably to a group of evolved nitrogen-rich main-sequence stars.