2021-10-16

Scientists explore the “common envelope” stage of the evolution of double neutron stars

By yqqlm yqqlm

Scientists explore the “common envelope” stage of the evolution of double neutron stars

the common cladding phase is a special result of quality transfer events. It begins with (at least) the overflow of the Roche lobe of one of the stars and is caused by a dynamic instability factor. In a simple version, the stellar envelope of the mass transfer star — the donor star — expands and devours the entire binary, creating a new system composed of an internal compact binary and a shared common envelope. The interaction between the internal binary and the common cladding leads to resistance, and the dissipated gravitational energy is transferred to the common cladding, which may lead to its ejection. A successful ejection shows that a compact binary can be formed. But what does “successful ejection” mean

Scientists explore the “common envelope” stage of the evolution of double neutron stars(1)

in order to explore the common cladding stage with three-dimensional hydrodynamic model, scientists try to solve the possible results of common cladding evolution by considering the response of one-dimensional star model to cladding removal. In a recent study, scientists focused on the common cladding stage of donor stars with neutron star companion stars. We simulate the common cladding phase by partially or completely removing the cladding of the donor star. After the star was stripped, the researchers tracked its radial evolution. In the most extreme cases, the results are consistent with expectations. If you remove all the cladding, the stripped star is still compact. Or, if most of the cladding is left, the stripped star will then expand a lot. The question is: what happens between these two extremes

studies show that when most but not all of the cladding is removed, the star will experience a short edge contraction stage (

this study is a step forward in understanding the common cladding stage and the formation of double neutron stars. The results mean that a star can be stripped without experiencing Roche valve overflow immediately after the common cladding, which is a possible condition for successful cladding injection. It also shows that the stripped star retains several strange, hydrogen poor materials of solar mass on its surface. Although this amount of hydrogen is small, it may be observed in the spectrum of stars and play a role in exploding into supernovae at the end of their life. Although a comprehensive understanding of the common cladding phase is still elusive, researchers are connecting the evolution and fate of systems that have experienced the common cladding phase