Yesterday my friend on Discord sent me an article on this new black hole called The unicorn
and i got very intersted and i found these articles for other people to read up on
https://www.space.com/tiny-black-hole-unico...losest-to-earth

and here is the arxiv.org article
https://arxiv.org/abs/2101.02212

apparently it orbits a big bloated red giant star

I wouldn't have any context for this if I hadn't recently listened to this episode of PBS Spacetime (consistently amazing content, by the way), where Matt O'Dowd explains how a recent gravitational wave observation helps clarify the boundary/mass gap between neutron stars and black holes ... sounds like this is another related piece of that puzzle? Neat stuff.

Given that the star has a companion, the first thing I think of is Type 1a supernovae. If a white dwarf (the pre-nova star) in a binary system can gradually accumulate matter from its companion until the white dwarf suddenly goes supernova, could the Unicorn be part of a similar pair, but where a neutron star gradually accumulated matter from its companion until it suddenly becomes a black hole? In which case, it would initially have basically the minimum possible mass for a black hole, and not be indicative of the minimum possible mass for a black hole to form directly from the collapse of a giant star?

There is also the interesting / bizarre possibility that colliding stars of degenerate matter (electron, proton, neutron or quark) could form a "synestia"- https://www.ucdavis.edu/news/synestia-new-t...lanetary-object

In that case, the central core collapses to a fly-weight black hole (boxing reference) while the remainder of the degenerate matter is flung out into a torus where it is under comparatively low gravity.

Hmm, is it theoretically possible to create a "degenerate matter eutectic"?
In simplest terms, you'd have a white-dwarf "sauce" mixed in with a neutron star's "nuclear pasta"?

Greenish, that Matt Dowd video is a very good connection to make. The Unicorn paper discusses LIGO discoveries as comparable cases; they may not be the same thing, but they're part of the same range of mass and density and presence in a coorbital binary. The Dowd video gives a good sense of what we do and don't know about bodies in this mass range so far.

yeah scientists use what they already have (other black holes) to compare to something new (The Unicorn)

could Unicorn and its companion star once ben a binary star system, and "The Unicorn" died first and became a neutron star then sucked material from its companion witch is now a red giant and became a black hole as JRehling said in his comment