Mysterious ‘Great Dimming’ of giant star Betelgeuse finally explained
When the nearby red supergiant started acting strange, some speculated it could be on the verge of going supernova. Now scientists know what was really happening.
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Tau.Neutrino said:
Mysterious ‘Great Dimming’ of giant star Betelgeuse finally explainedWhen the nearby red supergiant started acting strange, some speculated it could be on the verge of going supernova. Now scientists know what was really happening.
more….
Ha!
I had an explanation of that within a day of a sudden brightening being discovered (15 or so years ago) based on AAVSO observations. Let’s see if they agree with me.
My explanation was that Betelgeuse is a semi-regular star with a pseudo-period not to different to a year. Because it could only be observed highest in the heavens from Earth during a short month or two, successive years of observations showed no change in brightness until the period changed a but and suddenly it appeared to brighten, leading to newspaper claims that it looked like it was exploding. But that was just within the normal range of variation.
Wikipedia says “A pulsating semiregular variable star, Betelgeuse is subject to multiple cycles of increasing and decreasing brightness due to changes in its size and temperature. … a deeper-than-normal 425 day period are the driving factors.”
So I said nearly a year, 365 days. Wikipedia says 425 days. Pat on the back for mollwollfumble.
Anyway, I said this long before the period of ‘great dimming’ even occurred.
> We have directly witnessed the formation of stardust
Good. It was known to have a dust shroud nearly 20 years ago,
> the Great Dimming was actually caused by just such a mass loss incident. The star expelled a clump of gas near a region on the southern portion of its surface that developed a cold patch shortly thereafter. This cooling of the ejected gas allowed it to condense into literal stardust.
Good observation.
> In addition to explaining the weird behavior of Betelgeuse …
It doesn’t actually explain it, because it doesn’t explain how the dust came to be expelled in the first place.