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Keywords:

  • asteroseismology;
  • subdwarfs

ABSTRACT

We present our discovery of a new hybrid pulsating subdwarf B (sdB) star, J08069+1527. The effective temperature and surface gravity of 28 500 ± 400 K and 5.37 ± 0.04 dex, respectively, place this object inside the instability strip and also among other pulsating hot subdwarfs of a hybrid nature, right next to another fascinating star: Balloon 090100001. From this proximity, we anticipated this star could pulsate in both high- and low-frequency modes. Indeed, our analysis of photometric data confirmed our prediction. We detected two peaks in the high-frequency region and two other peaks at low frequencies. In addition, the amplitude of the dominant mode is very high and comparable to the dominant peaks in other hybrid sdB stars. Since this star is bright, we performed time-series low-resolution spectroscopy. Despite a low signal-to-noise ratio, we were able to detect the main peak from these data. All our results strongly indicate that J08069+1527 is a high-amplitude pulsating hot sdB star of hybrid nature. By analogy to the other pulsating sdB star, we judge that the dominant mode we detected here has radial nature. Future stellar modelling should provide us with quite good constrains as p and g modes presented in this star are driven in different parts of its interior.