Only supernovas within 50k light years will be counted.

Market will extend until a supernova explosion is detected within 50k ly from earth at which point the supernova progenitor will be selected as the answer.

Feel free to add other canidates, but please make sure they are within 50k ly.

Any supernova type counts, but it has to be a supernova, not something like a neutron star merger, or other exotic event.

If there's no consensus about wether an event is a supernova or not, I will try to wait until the controversy is resolved and may refer to sources such as wikipedia or notable scientific publications