[astrosi]

Unlikely, dead dark stars being dark matter candidates is a theory known as MACHOs (massive compact halo objects)

If they exist we would expect to detect them as they pass between another star and earth creating a gravitational lens. You can estimate the number of these MACHOs by looking at a bunch of stars for a long period of time and counting the number of microlensing events you see.

A team did this in 2000 and found that while there were some events, there weren't enough to explain all of the dark matter around the Milky Way. https://arxiv.org/abs/astro-ph/0001272

[hairytrog]

Dark matter is probably a grouping of several phenomena like this. Should not discount MACHOs just because it doesn't explain all the dark matter observations. I think I remember reading in Carroll's Astrophysics Intro that MACHO's can explain about 10-20% of dark matter. Dark matter could be potentially be explained fully by multiple dark matter explanations, each adding to the overall phenomena.

[mjevans]

Could also be some mix of some of the proposed answers, and possibly even things that haven't yet been considered. To contrast, sort of like performance improvements in new CPUs aren't any one single thing but a lot of little incremental improvements.

[_0w8t]

The graveyard is outside traditional boundaries of Milky Way. So the stars there do not contribute to microlensing.

[AtlasBarfed]

That's not how gravity works. The "kicks" from star death aren't shooting them to the outside of the galazy where they just park.

The "kicks" are just tranforming the galactic orbital path from the typical "visible star path" to a different set of paths. The objects still would pass through the visible layer at some point, so the lensing events would still occur.

You know, assuming the described calculated results are true.

[_0w8t]

When the remains form surely they contribute to microlensing. But after they out of the visible Galaxy boundary, they stop. And given the end up 2-3 times from the boundary, they spent the vast majority of the time there without contributing to lensing.

Now consider that according to the paper 30% is going to leave the Galaxy. Those after the initial travel will never contribute to anything.