A study of chemical abundances, rotational velocities, and orbital elements in single-lined spectroscopic binary stars in open clusters

• Published in: Monthly notices of the Royal Astronomical Society Vol. 527; no. 3; pp. 6211 - 6226
• Main Authors: Ramos, A A, Holanda, N, Drake, N A, Rain, M J, Maia, F F S, Daflon, S, Pereira, C B
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 01-01-2024
• Subjects: A stars; Abundance; Aluminum; Binary stars; Cerium; Cluster analysis; K stars; Lanthanum; Lithium isotopes; Magnesium; Open clusters; Orbital elements; Parameters; Rotational spectra; Spectroscopic analysis; Spectrum analysis; Stellar evolution; Zirconium; (stars:) binaries: spectroscopic; stars: fundamental parameters; stars: abundances
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stad3632

ABSTRACT
Binary interactions play a significant role in stellar evolution. In this study, we present a comprehensive analysis of 17 single-lined spectroscopic binary stars and identify two more as ‘yellow stragglers’, in the context of 15 young open clusters with ages younger than 1.0 Gyr. High-resolution spectroscopy ($R\, \approx \, 48000$) was employed to determine atmospheric parameters and chemical abundances of various elements including Li, C (C2), N (12CN), O, Na, Mg, Al, Ca, Si, Ti, Ni, Cr, Y, Zr, La, Ce, Nd, and Eu, and compared them with the abundances of stars reported in the literature. The projected rotational velocities ($v\, \sin \, \mathrm{ i}$) of 17 stars were determined via the spectral synthesis method. For two stars, we analyse the phenomenon of yellow stragglers based on their spectra and colour–magnitude diagram. Our $v\, \sin \, \mathrm{ i}$ results exhibit excellent agreement with previous studies in the literature for four stars previously analysed. Furthermore, we found a similar set of chemical abundances between thin disc stars and the studied spectroscopic binaries, except for s-process elements, such as La, Ce, and Nd. Also, we confirm that yellow straggler stars are members of binary systems, specifically giant G/K-type stars paired with dwarf A-type stars. Finally, we investigated the relationships between chemical abundances, orbital parameters (obtained from the literature), and $v\, \sin \, \mathrm{ i}$, which can provide insights into the observed anomalies in 7Li abundance in two stars such as NGC 6694-14 and NGC 6709-303. Our findings suggest that the anomalous rotation and lithium enrichment observed in these stars are likely results of interactions within binary companions.