A lot of our sci fi would have to be updated.

A near-Earth supernova is an explosion resulting from the death of a star that occurs close enough to the Earth (roughly fewer than 100 light-years away) to have noticeable effects on its biosphere. Gamma rays are responsible for most of the adverse effects a supernova can have on a living terrestrial planet. In Earth's case, gamma rays induce a chemical reaction in the upper atmosphere...depleting the ozone layer enough to expose the surface to harmful solar and cosmic radiation. The gamma ray burst from a nearby supernova explosion has been proposed as the cause of the end Ordovician extinction, which resulted in the death of nearly 60% of the oceanic life on Earth. Source: http://en.wikipedia.org/wiki/Supernova#Impact_on_Earth So at only 4.3 light-years, I'm guessing that an Alpha Centauri supernova would generate a gamma-ray burst that could wipe out all, or practically all, life on earth. (Apparently the planet itself would not be affected much.) Fortunately Alpha Centauri is not a star thought to be a potential supernova in the foreseeable future. Betelgeuse (400-something light-years), however, is a candidate to blow any time.

Since we have yet to develop a good shield to gamma rays, a super nova at such a close range would probably sterilize our planet ... at the least, there would be a major extinction of at least 99% of all life forms on Earth, even those on the side away from the "flash" of the direct blast.

i'd live

That would certainly mean the end of our time here on AB, to say the least...

well we would be able to see it

Alpha Centauri is 4.37 light-years away a supernova less than 25 light years away would extinguish much of the life on Earth. The blast needn't incinerate our planet. All it would take is enough cosmic rays to damage the ozone layer and let through lethal doses of ultraviolet (UV) radiation and a supernova in Alpha Centauri would provide plenty to get the job done. ;+

As the known binary system die's , as it it now doing , the mass of each star will increse drawing them together in a deathly spiral , the speed of which will increase to a mind bowling pace , they will them collide in a massive double supernova style explosion. I believe the result would be catastrophic to life on earth. The cosmic shock-wave would probably interupt the orbits of our planets and imeadiately send us spiralling into our sun or off into the abys of space. Alternativelly the gama radiation alone would fry us all and leave our planet a barren rock.