BD UMi: Eccentric detached binary with γ Doradus type component

BD UMi is an Algol-type eccentric eclipsing binary with one of the components showing γ Doradus type pulsation. In this study we used the Transiting Exoplanet Survey Satellite (TESS) observations of the BD UMi system published in total of 16 sectors. We obtained the minima times of the eclipsing system and refined new light elements by using (O - C) technique. Out-of-eclipse variation related to the pulsation was analysed in the frequency domain and g-mode pulsations were detected at frequencies < 2d^-1 . We analysed the light curve of the system and obtained the physical and geometrical parameters of the components by using the well-known Wilson-Devinney code.

We found that the amplitude and frequency of the pulsation are variable and obtained three significant frequency as f₁ = 0 . 588d^-1 , f₂ = 0 . 746d^-1 , and f₃ = 0 . 140d^-1 which can be used as mean frequencies of the pulsator.

We found that the primary component is a γ Doradus type star. In this work the BD UMi system has been analysed in detail for the first time and we obtained masses and radii of the primary and secondary components as M₁ = 1 . 743 ± 0 . 011M_⊙ , M₂ = 1 . 734 ± 0 . 014M_⊙ and R₁ = 1 . 937 ± 0 . 004R_⊙ , R₂ = 1 . 266 ± 0 . 002R_⊙ , respectively.