IM Per is a triple star system whose eclipsing pair masses and radii are accurate to within 1%. The Transiting Exoplanet Survey Satellite (TESS) light curve of the program target exhibits partial eclipses and multiple oscillations with millimagnitude-level amplitudes. It is found that the oscillations affect eclipse timing measurements. Binary modeling of the high-quality TESS data indicates that the eclipsing components of the triple system are twin dwarfs with parameters of M 2/M 1 = 0.995, R 2/R 1 = 0.901, and Δ( – ) = 12 K in an eccentric (e = 0.049), detached configuration. The third light of l 3 = 0.054 may mostly come from a G-type tertiary companion. Our predicted parallax of 1.52 ± 0.09 mas is concurrent with the Gaia measurement of 1.52 ± 0.05 mas. Multifrequency analysis of the outside-eclipse residuals reveals 22 significant pulsation signals: 4 in the gravity-mode region (0.03−2.22 day−1) and 18 in the pressure-mode region (9.19−25.12 day−1). Of the low frequencies, f 11 and f 14 are orbital harmonics that can be identified as tidally excited modes. The pulsation periods and constants for the high frequencies, and the position in the Cepheid instability strip demonstrate that the pulsating component of IM Per is a δ Sct variable.

We present the Transiting Exoplanet Survey Satellite (TESS) photometry and our high-resolution spectra of the EL CVn–type star 1SWASP J084356.46–113327.5 (WASP 0843–11), which consists of an F-type main-sequence (MS) star and a hotter low-mass helium white dwarf precursor (pre-He WD). In a spectral analysis, double-lined radial velocities (RVs) were obtained for the first time. From a simultaneous analysis of the TESS light and RV curves, the masses, radii, and temperatures of each component were determined to be M 1 = 1.733 ± 0.031 M ⊙, M 2 = 0.220 ± 0.008 M ⊙, R 1 = 2.094 ± 0.013 R ⊙, R 2 = 0.331 ± 0.003 R ⊙, T 1 = 6960 ± 120 K, and T 2 =9870 ± 310 K, respectively. According to their physical properties, the primary and secondary stars are located on the instability strips of δ Sct/γ Dor hybrids and extremely low-mass WDs, respectively. We applied multiple frequency analyses to the residual light curve after subtracting the binarity effects and detected a total of four independent frequencies. A frequency of f 3 = 1.6356 day−1 in the low-frequency region was reminiscent of γ Dor stars, while the other three frequencies of f 2, f 15, and f 18 in the high-frequency region (150–196 day−1) are probably related to pre-He WD components. Our results demonstrate that the more massive MS primary star of WASP 0843–11 is a γ Dor pulsator, whereas the hotter secondary component is a pre-He WD with high-frequency pulsations.

In this paper, we present Transiting Exoplanet Survey Satellite (TESS) photometry and high-resolution spectra of the short-period Algol EW Boo. We obtained double-lined radial velocities (RVs) from the time-series spectra and measured the effective temperature of the primary star as T eff,1 = 8560 ± 118 K. For the orbital period study, we collected all times of minima available for over the last 30 yr. It was found that the eclipse timing variation of the system could be represented by a periodic oscillation of 17.6 ± 0.3 yr with a semiamplitude of 0.0041 ± 0.0001 day. The orbital and physical parameters were derived by simultaneously analyzing the TESS light and RV curves using the Wilson–Devinney (WD) binary star modeling code. The component masses and radii were showed over 3% precision: M 1 = 2.67 ± 0.08 M ⊙, M 2 = 0.43 ± 0.01 M ⊙, R 1 = 2.01 ± 0.02 R ⊙, and R 2 = 1.35 ± 0.01 R ⊙. Furthermore, multiple frequency analyses were performed for the light-curve residuals from the WD model. As a result, we detected 17 pressure-mode pulsations in the region of 40.15–52.37 day−1. The absolute dimensions and pulsation characteristics showed that the δ Sct pulsator was the more massive and hotter primary star of the EW Boo.

New high-resolution spectra of the eclipsing binary BD+47 378 were obtained on five nights between 2020 and 2021 with the Bohyunsan Observatory Echelle Spectrograph in Korea. We collected the TESS light curve of the system obtained from Sectors 17 to 18, which shows a flat bottom at the secondary eclipse, an O’Connell effect, and oscillation features. From the spectral analysis, the radial velocities (RVs) of the primary and secondary stars were obtained, and the temperature of the brighter and more massive primary component was determined to be 7140 ± 100 K. According to a simultaneous analysis of the double-lined RVs and TESS light curves, the masses and radii of both components are M 1 = 1.69 ± 0.03 M ⊙, M 2 = 0.80 ± 0.02 M ⊙, R 1 = 2.01 ± 0.01 R ⊙, and R 2 = 0.79 ± 0.01 R ⊙, respectively. The primary component of the system is located on the δ Sct and γ Dor instability strips. After subtracting the theoretical light curve from the TESS data, a total of four independent frequencies (5.7235 day−1, 6.2577 day−1, 6.9588 day−1, and 14.7675 day−1) were detected using the multiple frequency analysis. These frequencies are typical of a δ Sct pulsator. The results reveal that BD+47 378 is a detached system consisting of two main-sequence stars with a δ Sct type primary component.