LvChenglong, a Ph.D. student at the Chinese Academy of Sciences (CAS) Xinjiang Astronomical Observatory (XAO), and his colleagues constructed stellar models with four radial pulsation frequencies to reveal the evolutionary state of Scuti KIC 1573174.
On June 14, the findings were published in The Astrophysical Journal.
In observations, the Scuti stars provide a wealth of oscillation modes, with both radial and non-radial oscillations detected in the amplitude spectra. Different modes exhibit different propagation behaviors in the star and reflect different stellar structure properties.
The KIC 1573174 was discovered to be a quadruple mode Scuti star by the researchers. Because the star has multiple pulsation periods, the traditional period analysis method cannot obtain the period variation of the star accurately, so a different approach has been used to determine the period variation through the study of phase modulation.
The period change (1/P)dP/dt is obtained, and the fundamental and first overtone frequencies are -1.14 106 yr-1 and -4.48 106 yr-1, respectively. Using the stellar evolution programme MESA, a series of theoretical models based on the four radial frequencies were obtained. The observed fundamental frequency to first overtone frequency ratio is greater than that of the model, which could be due to the star’s rotation.
Furthermore, the results of the model revealed a consistent evolutionary state for medium- and high-amplitude Scuti stars. The proposed goal could aid in furthering our understanding of the distinction and relationship between high-amplitude and low-amplitude Scuti stars.