Tidally trapped pulsations in a close binary star system discovered by TESS

Probing the interior physics of stars through asteroseismology

“…Its data of high-mass stars is complementary to the Kepler data in terms of targets. BRITE revealed several more nonradial oscillation modes than what has been found in ground-based data for OB-and Be-type pulsators (Baade et al, 2016;Pigulski et al, 2016;Handler et al, 2017;Kallinger et al, 2017;Ramiaramanantsoa et al, 2018). Combined BRITE data and archival data assembled from extensive ground-based (multisite) campaigns or data that are currently being assembled by the NASA Transiting Exoplanet Survey Satellite (TESS) (Ricker et al, 2016) hold good potential for asteroseismology of the highest-mass nearby stars with highamplitude oscillation modes to perform modeling of their interior properties.…”

“…Combined BRITE data and archival data assembled from extensive ground-based (multisite) campaigns or data that are currently being assembled by the NASA Transiting Exoplanet Survey Satellite (TESS) (Ricker et al, 2016) hold good potential for asteroseismology of the highest-mass nearby stars with highamplitude oscillation modes to perform modeling of their interior properties. Handler et al (2019) illustrated the TESS potential in revisiting bright B-type pulsators discovered from the ground but lacking sufficient identified pulsation modes. The nominal TESS mission is scanning almost the full sky, delivering highprecision space photometry for millions of stars with time FIG.…”

“…19. Examples were given by Debosscher et al (2013), Hambleton et al (2013Hambleton et al ( , 2016Hambleton et al ( , 2018, Murphy et al (2013), ), Borkovits et al (2014, Guo, Gies, and Fuller (2017), Guo, Gies, and Matson (2017), Bowman, Johnston et al (2019), , Handler et al (2020), Southworth et al (2020), and Kurtz et al (2020), where Handler et al (2020) and Kurtz et al (2020) reported the first cases of tip-tilted oblique binary pulsators. Hardly any of these binary systems have yet been modeled asteroseismically, according to Fig.…”

“…Although major achievements were obtained in the decade after this first review on asteroseismology by Brown and Gilliland (1994), mainly from ground-based multisite network campaigns for pulsating white dwarfs (Winget et al, 1991), hot subdwarfs (Kilkenny et al, 1999;Brassard et al, 2001), roAp stars (Kurtz et al, 2005), δ Sct stars (Breger et al, 2005), and β Cep stars (Handler et al, 2006), the plea by Brown and Gilliland (1994) to replace photometric ground-based network observations with data to be taken with spaceborne telescopes was fully justified. Space data not only would provide much lower noise by avoiding disturbances due to Earth's atmospheric variability but also would allow one to increase the duty cycles of the data significantly, without large daily interruptions of the time series that plague data from ground-based observatories.…”

The roAp Stars Observed by the Kepler Space Telescope

“…This configuration results in a variable light curve over the rotation period of an Ap star, as chemical spots often form at the magnetic poles and provide a brightness contrast against the photosphere. The pulsation axis in a star is the axis of greatest deformation; in most stars it is the rotation axis that serves to break spherical symmetry, and in some binary stars it is the line of apsides (Handler et al, 2020;. In the case of the Ap stars, it is the magnetic field, which can be of order 30 kG (e.g., Babcock, 1960;Freyhammer et al, 2008;Mathys, 2017), that causes the most significant deviation from spherical symmetry, and so the pulsation axis is closely aligned to the magnetic one (e.g., Shibahashi and Saio, 1985a;Shibahashi and Takata, 1993;Bigot and Dziembowski, 2002;Bigot and Kurtz, 2011).…”