Chemically peculiar stars on the pre-main sequence

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Authors	KUEß Lukas PAUNZEN Ernst FALTOVÁ Nikola JADLOVSKÝ Daniel LABAJ Matúš MESARČ Marko MONDAL Prapti PRIŠEGEN Michal RAMEZANI Tahereh SUPÍKOVÁ Johana SVAČINKOVÁ Kateřina VÍTKOVÁ Michaela XIA Caiyun BERNHARD Klaus HÜMMERICH Stefan
Year of publication	2024
Type	Article in Periodical
Magazine / Source	Astronomy & Astrophysics
MU Faculty or unit	Faculty of Science
Citation
Web	https://ui.adsabs.harvard.edu/abs/2024arXiv240508946K/abstract https://www.aanda.org/articles/aa/full_html/2024/07/aa48926-23/aa48926-23.html
Doi	http://dx.doi.org/10.1051/0004-6361/202348926
Keywords	Stars: chemically peculiar; Stars: pre-main sequence; Stars: variables: general; open clusters and associations: general; Hertzsprung-Russell and C-M diagrams
Description	Context. The chemically peculiar (CP) stars of the upper main sequence are defined by spectral peculiarities that indicate unusual elemental abundance patterns in the presence of diffusion in the calm, stellar atmospheres. Some of them have a stable local magnetic field of up to several kiloGauss. The pre-main-sequence evolution of these objects is still a mystery and contains many open questions. Aims. We identify CP stars on the pre-main sequence to determine possible mechanisms that lead to the occurrence of chemical peculiarities in the (very) early stages of stellar evolution. Methods. We identified likely pre-main-sequence stars by fitting the spectral energy distributions. The subsequent analysis using stellar spectra and photometric time series helped us to distinguish between CP and non-CP stars. Additionally, we compared our results to the literature to provide the best possible quality assessment. Results. Out of 45 candidates, about 70 % seem to be true CP stars or CP candidates. Furthermore, 9 sources appear to be CP stars on the pre-main sequence, and all are magnetic. We finally report a possible CP2 star that is also a pre-main-sequence star and was not previously in the literature. Conclusions. The evolution of the peculiarities seems to be related to the (strong) magnetic fields in these CP2 stars.