Now, I know what you’re saying – 15.5 is bigger than 13.4, so why was the system fainter? Didn’t I mean it was brighter?
Our way of describing something as bright in the night sky is weird, but all you have to remember is the smaller the number, the brighter the object! So a star that is magnitude 2 is much, MUCH brighter than a star that is magnitude 8!
So, back to FO Aquraii. We found that it was fainter than usual. And this is important because people have been looking at this system since 1923, and it had never become fainter before! So we’re currently working on explaining why it’s so faint, and why it’s so important to study objects like this.