The pulsating stars in eclipsing binaries are particular attractive objects for the study of stellar structure and evolution since they exhibit eclipses and pulsations simultaneously. The orbital motion and light eclipse allow us directly determine accurate stellar parameters such as mass and radius for each component. Asteroseismology, by comparing the model frequencies with the observed modes, not only provides an independent determination of fundamental physical parameters of the pulsators, but also offers significant insight into the interiors of the star.

On June 4, The Astrophysical Journal published a theoretical study on an eclipsing binary. Dr. CHEN Xinghao from Yunnan Observatories of Chinese Academy of Sciences and his cooperators discovered an Algol-type eclipsing binary KIC 10736223 that has just undergone the rapid mass-transfer stage.

As a typical classical Algol system, KIC 10736223 is formed through mass exchange and mass-ratio reversal. The researchers modeled the light curve and found its secondary star almost filling its Roche lobe. This feature probably indicates that the binary system just passed a rapid mass-transfer stage.

In order to ascertain this discovery, they constructed two grids of theoretical models to reproduce the pulsation frequencies. They found fitting results of mass-accreting models agree well with those of single-star evolutionary models. And they found that the pulsator is an almost unevolved star with an age between 9.46 and 11.65 Myr for single-star evolutionary models and 2.67–3.14 Myr for mass-accreting models.

They therefore identified KIC 10736223 to be an Algol system that has just undergone the rapid mass-transfer process.

"The mass-transfer process is still the largest uncertainties. The discovery of KIC 10736223 provides a new constraint on this process, and is of great scientific significance to improve the present theory of stellar structure and evolution.” said Dr. CHEN.

Contact:

CHEN Xinghao
Yunnan Observatorie,CAS
chenxinghao@ynao.ac.cn