Could an astronomer weigh in as to why the dimming effect isn't due to a 'rogue' blackhole entering orbit with the star and both blocking light and draining material from the star? I haven't seen that hypothesis dismissed yet.
Not entirely sure why, but I suspect because they haven't been able to determine if there's any lensing going on of the star that you'd expect to see if something like that entered the system. But I do believe that they'd see higher energy (x-ray, gamma?) bursts if it was removing material from the star which would lead to a different kind of variability. We know roughly what that should look like because of other binary systems where one star is being consumed and I don't think I've seen anyone say this looks a bit like that.
Though I'd love to have someone that's actually knowledgeable on the subject to weigh in and tell me how wrong I have this.
There wouldn't be any observed lensing because you have to be the right distance between the lens and the source for that to be observed. (For objects of comparable mass, the lens has to be roughly halfway in between the source and the observer) But if there were a black hole accreting matter from the host star, there would be an accretion disk which would be visible in X-ray.
A black hole is also too small to explain the drop in brightness. That would require something planet-sized, but a black hole is only about the size of a city.
Stellar ones have a soft upper boundary. If they are so old and massive that they become planetary or even stellar sized - well the'd start drawing stealing a good chunk of the host galaxy and form their own one - with blackjack and hookers. I.e. a flickering star would be the least of your worries ;-).
The mass of the star before it went and formed a black hole. The bigger a star, the hotter it is, and the more evaporates from the surface, and the shorter it lives. Large blackholes grow through things falling into them.
Oh I read the parent comment as black holes having a soft upper boundary. Is that the case? Or if more stuff falls in they just get bigger (minus Hawking radiation)?
So there is a complication, which is space is filled with vast amounts of nothingness. For a black hole to get bigger objects need to be on a collision course with it, which is somewhat unusual. A black hole doesn't behave any differently from the same mass as something not a black hole. So once a star turns into a black hole, the accretion disk is usually remnants/maybe more if it is in a nebula. Once that's gone, that's it for growth.
Schwarzchild radius means black holes are small. To dim the light from a star you need something very high in surface area whereas black holes by definition are the most compact objects in the universe
the star isn't distorted or emitting x ray radiation in such a way as to suggest it's within close vicinity of a black hole . A black hole is too small to block light . I'm pretty sure scientits have rule that out
