Type 1a Supernovae are a very special type of explosion that involves binary star systems. We aren’t really sure what causes them yet – it is either one very dense star called a white dwarf eats a star like our Sun until the white dwarf gets too big, and then it blows up (we call this the single-degenerate channel, and here’s what we think those systems look like: https://i.ytimg.com/vi/5YZkAoR3WLE/maxresdefault.jpg). The either scenario is when 2 white dwarfs ram into each other, and then explode (this is the double-degenerate scenario).
Figuring out which one of these scenarios it is (or even if it’s another scenario that we haven’t even thought of) is very important because these explosions are used to constrain how fast our Universe is expanding. In fact, the Nobel Prize in Physics was awarded for this type of work in 2011 – so figuring out which scenario it is will probably be another Nobel Prize!