A report by Susanna Kohler on 15 April 2020 at the American Astronomical
Society reports on observations of the recent dimming and brightening
of Betelgeuse made by the SOFIA airborne observatory.
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Originally Posted by Susanna Kohler, AAS
Scientists have proposed two main explanations for Betelgeuse’s recent dimming: either it’s an intrinsic cooling of the star’s photosphere, or Betelgeuse has thrown off dust that’s now lying between it and us, blocking some of its light.
Because infrared observations will be critical to exploring these options, NASA-DLR’s Stratospheric Observatory for Infrared Astronomy (SOFIA) planned an extensive campaign to look at Betelgeuse and its environment.
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Originally Posted by Susanna Kohler, AAS
Harper and collaborators explored Betelgeuse’s circumstellar envelope, the sphere of stellar material that flows off of and surrounds the star. In particular, the SOFIA/EXES observations are of two gas emission lines: singly ionized iron, and neutral sulfur. The authors compare observations of these lines from February 2020, when Betelgeuse was at its dimmest, to observations from 2015 and 2017, when Betelgeuse was at its normal brightness.
The team finds that the lines from the different observing cycles are very nearly the same, suggesting that Betelgeuse’s circumstellar flow has not been affected by whatever caused the star to dim — whether that’s changes in the photosphere or the presence of new dust in the sightline to the star. The observations also indicate that the heating from the stellar wind didn’t change during the dimming.
These results are one more piece in the puzzle of Betelgeuse’s strange behavior. And with additional observations from other SOFIA instruments soon to be analyzed, we can anticipate more news to come!
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Story here :-
https://aasnova.org/2020/04/15/obser...-stratosphere/
