SG-1 planned to detonate the star in a premature supernova, upon hearing the news that Apophis' fleet would arrive over Vorash, this was a chance to wipe him out once and for all. Major Samantha Carter planned to send a Stargate to the sun and dial P3W-451, the planet devastated by a black hole two years previously. The connection would make the star unstable. When Apophis' arrived, the star went supernova, destroying most of the fleet, as well as the entire system.
The blast wave of the star later caused SG-1's Ha'tak and Apophis' mothership to be knocked off course, took the ship into "hyperspeed", making the ship travel four million light years into another Galaxy. (SG1: "Exodus")
Nearly three years later, due to time dilation, the sun's matter hasn't actually reached P3W-451 yet, allowing SG-1 to rescue SG-10 from the planet. However, as they try to fix their ship's anti-gravity shield, the wormhole finally opens and the sun matter incinerates everything on the planet including Lieutenant Jonathan Reed of SG-10. The rest of SG-1 and SG-10 manage to escape in time. (SG1: "The Cost of Honor")