부산대학교 도서관

In this paper, we present the results of a comprehensive study of six eclipsing binaries whose components are confirmed or suspected Am stars. By combining long-term high-resolution CAOS spectroscopy and TESS photometry we have been able to accurately obtain the orbital parameters of each system as well as the atmospheric parameters of its components. We performed an in-depth chemical analysis and provided chemical abundances of C, O, Na, Mg, Si, Ca, Sc, Ti, Cr, Mn, Fe, Ni, Zn, Sr, Y, Zr, and Ba. From the solution of the light and radial curves, we have determined masses, radii, and temperatures with good accuracy. We observe apsidal motion in the eccentric system HD216429, in which the Rossiter-McLaughlin effect is also noted. We inferred the age of our targets by fitting isochrones on the HR diagram and find that both components in each system are properly described with the same isochrone, which reinforce our results. Furthermore, dynamical and evolutionary masses, independently obtained, show an excellent agreement. According to the out-of-eclipse variability shown in their TESS light curves and their position on the HR diagram, we claim the pulsating nature of the stars HD42954 (as delta Sct type) and HD151604 (gamma Dor). Based on the chemical analysis we corroborate that four of the systems studied here are formed by Am stars, while in the remaining ones (HD126031 and HD216429) only the primary component exhibits a peculiar composition. Additionally, the age distribution found in Am stars supports their suitability as age tracers in stellar populations.
Comment: 18 pages, 15 figures, paper accepted on A&A Main Journal