Well, Zombie Vortices, Actually

They sound like something from science fiction, from the most mysterious corners of the cosmos: Zombie Vortices. Yeah, I know, I cringed a little when I saw the term because there are already enough “weird” things attributed to space exploration by uneducated media practitioners, but this one actually fits.

To understand what zombie vortices are, let’s go back to the early history of our own solar system. Back when it was nothing more than a cloud of gas and dust, swirling around in space.  There were no planets yet, and the Sun was still forming. It was surrounded by a vast circumstellar disk of gas, dust, chunks of rock, and protocomets. As the Sun formed, that whole cloud of “stuff” began spinning faster and faster. But, if it had gotten to spinning too fast, the Sun might not have finished forming. It might have been starved of material and become only a brown dwarf (an object too hot to be a planet and too cool to be a star).

So, somehow, that Frisbee of gas and dust needed to LOSE angular momentum. This was so clumps of  material could continue to fall inward to the cloud core and contribute to the ever-growing infant Sun. Astronomers at University of California at Berkeley working on a model of  how stars form from whirling clouds of gas and dust also suspected that other theories, such as the interplay of material in the disk with magnetic fields, also didn’t explain how a disk could lose some of its angular momentum. So, they looked at how the density of gas in a cloud changes, and what such changes could do to a disk as it contributed to its forming star.

It turns out that changes in disk density makes parts of the cloud very unstable. And that leads to the formation of vortices in the disk. You’ve seen a vortex when you watch water swirl down a drain, if you’ve looked at pictures of Jupiter with its vortices, cloud whirlpools and storms. Such “dead zones” could destabilize the disk, and that would allow material to continue accreting onto the newly forming star. Subsequent generations of these “zombie vortices” could further affect the disk, and enable the continuing formation of the star.

There’s more work to be done by the astronomers to refine their model, but if this works out, it could go a long way toward explaining some more of the details of starbirth, and give further insight into our own star formed some 4.5 billion years ago.