A planetary collision: ASASSN-21qj

What happens when two planets collide? Astronomers were fortunate enough to have unique views of the collision and aftermath of 2 Neptune sized planets colliding. When these ice-giant planets crashed they left behind a hot, loose ball of gas, dust and rocks, with an even hotter core. Over hundreds of years this with thin out around the orbit, the core will grow by accretion and moons may even form from the debris.