Hydrodynamical simulations for the common-envelope wind model for Type Ia supernovae

Ph.D. candidate Cui Yingzhen and Prof. Meng Xiangcun from the Yunnan Observatories of the Chinese language Academy of Sciences (CAS) carried out hydrodynamic simulations on the common-envelope wind mannequin of Kind Ia supernovae (SNe Ia), and revealed the mass loss mechanism and the principle observational options of white dwarf binaries within the common-envelope wind phase.

The examine was printed in Astronomy & Astrophysics.

SNe Ia are a number of the most energetic occasions within the universe. They’re used as cosmological distance indicators, which have led to the invention of the accelerating growth of the universe.

Probably the most fashionable progenitor fashions of SNe Ia is the single-degenerate mannequin, by which a carbon-oxygen white dwarf accretes materials from a non-degenerate companion star to extend its mass, and ultimately undergoes a thermonuclear explosion. The issue with this mannequin is that when the mass switch charge exceeds a sure vital worth, the accreted envelope of the white dwarf expands and ultimately varieties a standard envelope across the binary system, which can forestall the prevalence of SNe Ia.

The common-envelope wind mannequin is a modified single-degenerate mannequin that may in precept deal with the above-mentioned downside by suggesting a powerful mass loss on the floor of the frequent envelope. Nevertheless, it isn’t clear how the mass loss on the floor of the frequent envelope arises and what the observational traits of such techniques are.

The researchers carried out detailed hydrodynamic simulations of common-envelope wind mannequin and located that such techniques are all the time dynamically unstable and consequently produce dramatic mass loss, leading to an envelope mass of just a few hundreds of solar mass.

By analyzing the inner construction, they discovered that this instability was pushed by ionization-recombination processes of hydrogen and helium within the envelope, the identical mechanism because the pulsating excitation of classical Cepheids. Within the Hertzsprung-Russell diagram, the middle of the evolutionary trajectory of the common-envelope wind mannequin was additionally situated inside the classical Cepheid instability strip, implying that this method could seem as periodic variable stars.

This end result can present theoretical steerage for the next observational seek for progenitor system of SNe Ia.