A team of astronomers peering through Chile’s Very Large Telescope just realised that HR 5171 A, a massive star in the Centaurus constellation, is actually twice as big as previously thought. They already thought it was pretty big — but it’s actually the biggest yellow star they have ever seen.
How big is biggest? This star is 1300 times the size of the sun. It’s so big that it’s practically absorbing its smaller companion star. The two of them form a giant, peanut-shaped star system that’s so big it would devour nearly the entire solar system if it were located where our sun is. That’s why they call this size star a hypergiant.
That’s a lot of heat and fire. It is not, however, the biggest star ever discovered. A red star called UY Scuti currently holds the title of biggest star in the universe. It’s 1700 times larger than the sun. Nevertheless, HR 5171 A is big enough to be included in the top ten biggest stars found so far. Given the massive gulf between how big we thought this star was versus how big it actually is suggests that this list will need updating as we start peering into the cosmos with bigger better telescopes.
The field around HR 5171 A