One of the most famous and easily recognizable constellations in the night sky, Orion is already on most stargazers’ radar. But recently, one of its brightest stars, Betelgeuse, has become even more famous by simply becoming less bright.
A red supergiant star so large it would completely fill the inner solar system if we put it at the sun’s location, Betelgeuse is approaching the end of its lifespan, and will literally go out with a “bang,” exploding as a supernova at some point in the 100,000 years – or sooner! At a distance of about 600 light years, Betelgeuse is far too distant to cause any damage to our cosmic neighborhood, but when it does explode, it could appear bright enough to see during the day!
Like most stars of its class, Betelgeuse has natural variations in brightness, but as you can see from the graph above (a light curve plotting brightness over time), recently the star has become unusually dim (although still easily visible from even light polluted skies). Does this necessarily mean that Betelgeuse is getting ready to blow? Probably not, but it is still interesting to astronomers. If you would like to join in the international campaign by the AAVSO (American Association of Variable Star Observers) to closely monitor Betelgeuse’s latest hi-jinks, you can learn how to observe variable stars using their 10-star tutorial [https://www.aavso.org/10-star-training]. One word of warning – Betelgeuse is very red, so make sure you make quick glances between it and your comparison stars to avoid the Purkinje effect (an optical effect in which red stars look brighter if you stare at them).
– Kristine Larsen, Past President, AAVSO