Videos

Convective Urca Process in Simmering White Dwarfs

In these videos we dive into the core convection region at the center of a hot dense white dwarf that is on it’s way to a supernovae. Our aim is to study the convective Urca process which may alter the evolution of the white dwarf prior to it’s incineration in a type Ia supernovae.

Rotating Snapshot in time

A key piece to studying the Convective Urca process is to study convection. In this video we look at a snapshot in time of the convection zone in the white dwarf. The red regions represent fluid that is moving away from the center (outflows) while the blue regions represent fluid moving inwward, toward the center of the star (inflows).

The video rotates around the star to enable seeing the full 3D structure of the flow.

Real Time Convection

These two videos track the convection and physics in real time. That is, the 25 seconds of video time correspond to exactly 25 seconds of physical time in the simulation. If we could slice into a white dwarf like the one modeled, we would see the flows move at the same speed as in these videos.

Sodium Mass Fraction

Sodium-23 (Na23) is an important isotope in the Convective Urca process. Near the center of the white dwarf, Na23 captures an electron and is converted to Neon. The process reverses further outside the white dwarf core (see yellow region of the video). Along with these reactions, convection can effectively mix Na23 around the convection zone which can be see in the video below. Of particular interest, the structure of convection allows for Na23 to “clump” on one side the the White Dwarf core.

Radial Velocity

We present two POVs of the WD star and it’s convection zone. On the Left, the net outflow (red) of convection is into the screen, with the blue inflows circling back around. On the right is a side profile the shows the outflows moving the right, before they circle back around the outside.