New Insights into Nova Explosions: Shear Mixing Effects

A recent paper titled "Hydrodynamical shear mixing in subsonic boundary layers and its role in the thermonuclear explosion of classical novae" by Marco Bellomo, Steven N. Shore, and Jordi José explores the dynamics within the boundary layer of classical novae. The boundary layer is a critical zone where the white dwarf's envelope meets the accretion disk, characterized by strong dissipation and intense vorticity.

The authors applied the critical layer instability (CLI) theory to understand how hydrogen-rich gas from the accretion disk mixes with the outer layers of the white dwarf. This mixing process alters the conditions necessary for a thermonuclear runaway (TNR), which is the explosive event that defines classical novae.

Their findings indicate that the mixing significantly changes the timing and intensity of the TNR. Specifically, the time to reach peak temperature is shorter, and the mass and velocity of the ejected material are greater than previously predicted. Additionally, the yield of lithium-7 is reduced by about an order of magnitude compared to standard models.

These insights could refine existing models of nova explosions, enhancing our understanding of these astronomical phenomena and their implications for stellar evolution and nucleosynthesis. The full paper can be accessed here.