The impactor device was very similar to a HEAT warhead; a high explosive shaped charge lined with copper. Detonation of the shaped charge turns the copper lining into what's called an explosively-formed penetrator of EFP [1]. Note that the device was separated from the main probe before use and the probe itself was below the horizon when the impactor was fired in order to avoid damage from debris.
9 million years ago is an intriguing dating for it. What would it be its origin? I guess a collision between two other asteroids. I wonder if it's possible to trace it back.
Maybe it’s just me but the title confused me... I thought they found artificial impacts on Ryugu, impacts that were artificial but not man made. Spoiler alert: the impact is man made and the article is about analyzing this impact.
I would say artificial implies man-made unless they buried the mother of all ledes.