Corrected entry: Carter says that the chance of depositing the heavy element inside the Katow sun while the element is en route is about 1%. However, hypothetically speaking, the actual chances would be infinitely smaller, in fact it would be near impossible. Simply consider the distance from earth stargate to the Katow stargate, the diameter of an average sun, and the time it takes for an object to travel through the gate (about 12 seconds). Taking the closest star to us (Alpha Centruri), at a distance of 4 light years, this means that the wormhole takes ~443ns (0.000000443s) to pass through the sun (using our sun diameter). Similarly, taking the diameter of the Milky Way as the distance to the furthest star in our galaxy, ~100000 light years, meaning the wormhole takes ~17ps (0.000000000017s) to pass through the sun. This means that the SGC would have to shut down the gate within a a maxmium of 443ns or a minimum of 17ps time gap. As we have previously seen, the stargate takes far longer to shutdown than these miniscule time lengths.Craig Bryant
Corrected entry: At the end of the show, SG1 travels back to the planet after the delivery of the heavy element into the alien sun to determine if the delivery of said material worked in restoring the sun to its original operational characteristics. However, if presumably they used the stargate to travel to and from the planet, then they would necessarily reintroduce the plutonium into the sun, causing a chicken-and-the-egg thing. The only way around this, which wasn't mentioned, would be to travel to a third planet and then to the world.