By Stacy Palen
This week, I draw your attention to this piece of news that neatly encapsulates many of the concepts that you might be teaching at this point in the semester! Betelgeuse’s recent variability may be caused by dust and pulsation—so no nearby supernova in the works for us this year. That’s typical 2020 for you right there. Disappointing, all around.
Below are some questions to ask your students based on this article.
1) Why were astronomers, earlier in the year, talking about Betelgeuse exploding as a supernova sometime soon?
Answer: Because it had abruptly become dimmer, and evolution to supernova was one possible explanation.
2. What key conclusion in this most recent study definitively rules out the supernova-soon scenario?
Answer: Betelgeuse is still fusing helium in its core, which means that it has a significant amount of time left before it makes the full, onion-like set of fusion shells that precede a supernova.
3) Typically, astronomers first determine the distance to a star and then infer its size from knowing something about its evolutionary state and where it sits on the H-R Diagram. What did astronomers do differently in this study?
Answer: In this study, astronomers used stellar seismology to find the size of the star first and then worked backwards to determine the distance. This distance agrees (it is within the error bars) with previously determined distances to Betelgeuse.
4) Will Betelgeuse eventually explode as a supernova (even if we don’t get to see it this year)?
Answer: Yes, because it is a red supergiant.
5) Will that affect life on Earth?
Answer: Probably not. It is too far away to have an impact on life on Earth, although it would become incredibly bright for a short time.