I really enjoy looking at images of the Sun from one of the several round-the-clock monitoring systems. It’s fascinating that the public can get access to almost real time images of the Sun and see what’s going on in several wavelengths. I’ve always hoped to see what other stars look like in the future, and today, that future is one step closer. Here’s a brand new picture of another star!
This is a real image of distant star π1Gruis, a star 350 times as massive as the Sun, in the southern hemisphere constellation Grus. The star is 530 light years from Earth, which makes this even more impressive. Taken with a 4-telescope instrument in Chile called PIONEER, the image was produced using an astronomical technique called interferometry, which uses these multiple telescopes in an array, giving the effect of using a single giant telescope. The result is a blurry but impressive image of a star that is among the most massive stars that can theoretically form.
Okay so there’s a blurry image of a distant massive star, what does it tell us?
An artist’s rendering of what the image shows will help out a bit:
You probably notice the two large bright blobs on the surface. These are massive convection cells. Convection cells are common, and occur in everything from boiling water to Earth’s atmosphere, to star’s like the Sun. When rising pockets of hot matter from within a star reach a high point, such as the surface, they are cooled by the surrounding space, and then fall back into the star, where they heat up again and repeat the process. The Sun has over 2000 convection cells, but massive stars like π1Gruis are thought to have just a few large ones. This is due to the lower surface gravity of massive stars. The new images support that theory.
Here is another great surface image of a star that can be seen in the Northern sky right now, the red super giant Betelgeuse.
Thought to be near the end of its life where it will explode as a supernova, the star is undergoing some intense wobbling and roiling. When it does explode, it will be bright enough to see in the daytime here on Earth.
Images like this can tell us about how stars behave at different stages of their lives, which helps us to understand their past and future. With additional observations and continuous monitoring, we can learn how features like these large convection cells evolve over time.