Researchers investigate properties of double white dwarfs with new mass transfer stability criterion

White dwarfs comprise a category of faint stars representing the endpoint of the evolution of intermediate- and low-mass stars. The mass of a white dwarf is the order of that of the sun, however a radius similar to that of the Earth. A pair of white dwarfs in orbit round their widespread heart of gravity known as a double white dwarf (DWD).

Researchers led by Dr. Li Zhenwei from the Yunnan Observatories of the Chinese language Academy of Sciences studied the affect of mass transfer stability criterion on the formation and properties of DWD populations within the galaxy.

This work was printed in Astronomy & Astrophysics on Jan. 13.

On the whole, a binary will expertise no less than one mass switch phase to supply a DWD. If the mass switch is secure, the donor star can switch mass to the companion on a protracted timescale. Quite the opposite, the unstable mass switch proceeds on a dynamical timescale, and the binary would enter into the widespread envelope phase.

Whether or not or not the mass switch is secure is especially decided by the mass switch stability criterion. Nonetheless, earlier mass switch stability criterion based mostly on polytropic fashions can not reproduce the orbital parameters of some noticed DWDs.

Ge et al. obtained the brand new mass switch stability criterion by adopting the adiabatic mass loss mannequin, or Ge’s mannequin. On this research, the researchers carried out a sequence of binary inhabitants synthesis with Ge’s mannequin, and confirmed that mass switch stability criterion performed an vital function within the formation and properties of DWD populations.

Evaluating findings with the earlier outcomes from the polytropic mannequin, they discovered that the merger fee distribution within the observations may very well be effectively reproduced in Ge’s mannequin with none tuning of parameters. The outcomes from Ge’s mannequin help the observations higher than what will be derived from the polytropic mannequin.

As well as, the researchers calculated the variety of detectable gravitational wave sources in Ge’s mannequin, and the outcomes present theoretical helps for future space-based gravitational wave detections.