Kinematics and chemical abundances of the B star HD 28248

TL;DR

This study provides a detailed chemical abundance analysis and orbital estimation of the B star HD 28248, revealing significant elemental enrichment and a disk-confined orbit, with implications for stellar evolution and galactic chemical gradients.

Contribution

First detailed elemental abundance and orbital path analysis of HD 28248 using non-LTE synthetic spectra and spectroscopic data from ESO.

Findings

HD 28248 shows significant Fe and O enrichment.

The star's orbit is confined to the galactic disk, about 4 kpc from its birthplace.

Elemental abundances do not follow standard galactic gradients.

Abstract

We perform a detailed elemental abundance study of the early-type B star HD 28248 and estimate its orbital path in the Galaxy. From the comparison of spectroscopic observations performed at the European Southern Observatory at La Silla in 2001/Oct/07 with non-LTE synthetic spectra using a new wrapper for the simultaneous fitting of several lines of a given atomic species, the abundances of He, C, N, O, Mg, Al, Si, P, S, Ar and Fe were determined for the first time. The radial velocity of HD 28248 has been also estimated from the positions of centroids of nine neutral helium lines and Mg ii 4481 A, allowing to calculate its right-handed Galactic space-velocity components U, V and W and estimate its orbital path in the Galaxy for the first time. Our chemical analysis depicted an outstanding enrichment of several atomic species, particularly [Fe/H] = +0.25 dex and [O/Fe] = +0.32 dex. The kinematic parameters show that its orbit is confined to the galactic disk with a scale height of 400 pc and the star has moved about 4 kpc from its birthplace to the current position. The elemental abundances do not follow the predicted [Fe/H] and [O/Fe] gradients currently established for the Galaxy. A hypothetical scenario for the contamination could be the mass transfer in a binary system during previous evolutionary phases.