[foxyv]

White Dwarves are probably the only non-mainline stars in the Universe we know a lot about. Neutron Stars and Black Holes are a lot more of a mystery because of our trouble reconciling Gravity and the Standard Model. This makes White Dwarves a lot more predictable than their more massive cousins. So we can actually simulate a lot of what they do.

https://en.wikipedia.org/wiki/T_Coronae_Borealis

However, in this case, we can observe the star slowly getting dimmer which is a pattern that has occurred in the past, a year before the star was about to do something. The process only takes about 100 years with a possible indicator a year in advance of the event.