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arXiv · 2608.03348

Unravelling Mass Transfer in Algols from Surface Abundances. I. Z Vulpeculae

Ahmet Dervişoğlu·Simge Adalalı·Ferhat Güney·Barış Hoyman·Timur Şahin·Ömür Çakırlı·Kresimir Pavlovski·David Mkrtichian·Peter De Cat·Patricia Lampens
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Abstract

The photospheric abundance pattern of the components is a sensitive probe of mass and angular momentum transfer in Algols. With the aim to trace the evolutionary history and disclosed efficiency of mass transfer in Algols we collected new high-resolution spectra for about a dozen Algols with the {\sc hermes} spectrograph at the Mercator Telescope on La Palma, Canary Islands. In the present paper, which is the first in the series, we present the results of a comprehensive analysis of Z Vul, a hot Algol-type system. We derived the absolute stellar quantities and elemental abundances for the components. The carbon-to-nitrogen (C/N) ratio is the most sensitive tracer of thermonuclear processing and mass transfer. It is found to be within expected value for gainer but donor lacks the severe C/N inversion traditionally expected for a deeply stripped star. An extensive grid of over three million evolutionary models was calculated with the Cambridge \texttt{STARS} code which allows determination of the best-fitting and all surviving models. Constraints from the He and CNO abundances indicate that Z Vul underwent an episode of nearly conservative mass transfer during the Main Sequence life-time of the originally more massive component (Case A). Our detailed chemical tagging confirms that the surface abundances of the mass-losing component represent the delicately stripped outer layers still not reaching the CNO-rich core. This underscores the need of coupling high-resolution spectroscopic abundances with interior stellar profiles to accurately reconstruct the evolutionary history of interacting binaries.

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Ahmet Dervişoğlu, Simge Adalalı, Ferhat Güney, Barış Hoyman, Timur Şahin, Ömür Çakırlı, Kresimir Pavlovski, David Mkrtichian, Peter De Cat, Patricia Lampens. 2026-08-04. Unravelling Mass Transfer in Algols from Surface Abundances. I. Z Vulpeculae. https://doi.org/10.1093/mnras%2Fstag1476

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