Supernova stars are not larger than our sun during their stable main-sequence phase. During this phase, they may be similar in size or even smaller than our sun. However, when a star reaches the end of its life and undergoes a supernova explosion, its size can change drastically.

During the supernova process, the star's core collapses, leading to a massive explosion that releases a tremendous amount of energy. This explosion causes the star's outer layers to expand rapidly, creating a supernova remnant. Depending on the size and mass of the original star, the supernova remnant can be vast and several times larger than our solar system.

In comparison to our sun, which has a diameter of approximately 1.4 million kilometers (864,000 miles), supernova remnants can span distances of hundreds to thousands of light-years. One of the most well-known supernova remnants, the Crab Nebula, is about 11 light-years across.

It's important to note that while the supernova remnant may be extremely large, the vast majority of its volume is composed of low-density gas and dust expanding at high velocities. The remnant itself does not contain a single, coherent "star" comparable to our sun in terms of mass and density.