The white dwarf with a metal scar is one thing that has never been seen before.

"This artist’s impression shows the magnetic white dwarf WD 0816-310, where astronomers have found a scar imprinted on its surface as a result of having ingested planetary debris. When objects like planets or asteroids approach the white dwarf they get disrupted, forming a debris disc around the dead star. Some of this material can be devoured by the dwarf, leaving traces of certain chemical elements on its surface". (ScitechDaily, Cannibal Star Discovered With Metal Scar – “Nothing Like This Has Been Seen Before”)

"Using ESO’s Very Large Telescope, astronomers found that the signature of these chemical elements changed periodically as the star rotated, as did the magnetic field. This indicates that the magnetic fields funneled these elements onto the star, concentrating them at the magnetic poles and forming the scar seen here. Credit: ESO/L. Calçada" (ScitechDaily, Cannibal Star Discovered With Metal Scar – “Nothing Like This Has Been Seen Before”)

The white dwarf WD 0816-310 is a magnetic white dwarf. That magnetic field can drive metals to its poles. But it is also possible that this star's metal scar formed in the case. That the impacting object was very small or the metal mass was so low, that metal cannot cover the entire white dwarf. 

White dwarfs are star remnants. Those stars used their fuel and then detonated in a nova eruption. The thing that makes white dwarfs interesting is that our sun's fate will be white dwarfs. Most of the white dwarfs are carbon stars. They are very dense objects. And that means they have quite strong gravity fields. 

Sometimes they pull some other object into the impact course. And if there is some kind of metal object, that metal will usually spread on that star's entire shell. The situation on white dwarf WD 0816-310 is that there is only metal at the pole of that dwarf star. 

That could mean that there was so little metal mass on the object that formed that scar on the white dwarf's pole. In that case, there is not enough metal that can cover the entire white dwarf. And that thing causes a very interesting hypothesis about the origin of that scar. Maybe a large metal asteroid impacted the white dwarf. But nobody knows the shape of that object. 

The small mass of metal can cause the theory that maybe the humanoid spacecraft formed that strange scar. The fact is that a small metal mass causes a situation where there is not enough metal to cover the entire white dwarf. 

Another interesting thing is that metal did not vaporize and fly to space or turn into some other element when that object impacted with white dwarf  WD 0816-310 causing a very high energy level. And that thing can cause a situation in which atoms melt together. Or they formed a fission that ripped the atoms into pieces. It is possible. That metal scar is formed from some very rare radioactive material. Or maybe some still unknown isotope or element formed that mysterious scar. 

https://scitechdaily.com/cannibal-star-discovered-with-metal-scar-nothing-like-this-has-been-seen-before/