A nuclear explosion is just as hot, but we don't really have anything big enough to melt a 22-mile long asteroid, or vaporize it, would be more like it.
核爆発は猛烈ですが 約35キロの長さの小惑星を溶かすほどの 威力を持っていません もしくは蒸発させるという方が しっくりきます