The Rhea release corresponded, as far as we can tell, with the collapse of the abnormally bright star which was named Caroline’s Star. This is a partial timeline of the collapse of the star and the formation of the nebula. Part 1, the brightening of the star, can be found here
All images were taken from the system of Vaajaita in Lonetrek.
As the days pass, so the shockwave moves outwards (at several times the speed of light!), leaving a void in the middle