Betelgeuse losing brightness

That image looks almost like Betelgeuse is being eclipsed…by something around as big as the star itself.

What evidence do we have that the star is in the middle of a solar system full of debris like nebular gas and dust?

There are photographs of Halley’s in 1910, and man, it was something to behold. Even accounting for the use of long exposure, it was huge. (Artists’ renditions are often very, very similar, too, suggesting a degree of illustrative honesty.) You are certainly right in that it was a lot easier to appreciate its full glory back when there was like one-hundredth as much urban light, but if you could, it was spectacular. The 1910 approach was very close even by its standards; its looking awesome was predictable.

I think at this point we can probably rule out the starspot explanation. I don’t think it’s possible for starspots to cover that large a percentage of the surface, or at least, anything that does cover that large an area operates on sufficiently different principles from the starspots we know that it should be called by a different name.

That image certainly looks consistent with the dust cloud hypothesis.

The ESO picture seems to show a lot of dust in the region around Betelgeuse. I think occluding dust cloud is the most likely hypothesis right now.

You are indeed great sages @Chronos and @Sam_Stone :

https://www.nasa.gov/feature/goddard/2020/hubble-finds-that-betelgeuses-mysterious-dimming-is-due-to-a-traumatic-outburst

Observations by NASA’s Hubble Space Telescope are showing that the unexpected dimming of the supergiant star Betelgeuse was most likely caused by an immense amount of hot material ejected into space, forming a dust cloud that blocked starlight coming from Betelgeuse’s surface.

Hubble researchers suggest that the dust cloud formed when superhot plasma unleashed from an upwelling of a large convection cell on the star’s surface passed through the hot atmosphere to the colder outer layers, where it cooled and formed dust grains. The resulting dust cloud blocked light from about a quarter of the star’s surface, beginning in late 2019. By April 2020, the star returned to normal brightness.

A little more data here: https://phys.org/news/2020-08-hubble-betelgeuse-mysterious-dimming-due.html

That’s always been a possibility, but it’s looking a lot less likely now that it’s both been explained and returned to its normal brightness.

Which post are you replying to?

A post which got nuked, saying that it was probably a sign of imminent supernova. The post itself was innocuous enough, but apparently the same poster went on to spam somewhere else. Spammers will do that sometimes, making a few innocuous posts before delivering their payload, to try to avoid detection.

Bad Astronomy:

Don’t panic! But Betelgeuse may be 25% closer to Earth than we previously thought

530 vs. 640 light years. Still no threat if it explodes, and apparently new data shows that that won’t happen for over a million years anyway.

Yeah right.
I’m not believing anything that star says ever again.