A Visual Tour of Stellar Companions Near the Sun

Have you ever wished that our Sun had a close companion? So when you looked up you saw not one but two stars in your sky? It’s not such a crazy idea. Our solar system only has one big heat source. But the Milky Way is filled with billions of stars and they come in all sorts of configurations. But if you want to look up into the nighttime sky and see some partner stellar systems, distance is going to play a really big role. The farther away the star is from you here on Earth, the harder it will be to resolve its partner if the two are really close together. But if they are fairly widely separated (think way beyond Pluto in our own Solar System) then you can catch both the stars careening through the Galaxy together. Recently a graduate student at Berkeley has produced a massive catalog of stellar companions. Kareem El-Badry used the European Space Agency’s Gaia eDR3 catalog to find 1.3 million of these objects! There are more than 1.3 billion stars to look through in the Gaia eDR3 catalog but the co-movers pop out pretty easily when you check to see which ones are closest to the Sun (so you can see both objects easily) and share a similar motion. I’ve been fascinated with visualizing this atlas of partnered stars. Kareem sent me the catalog pretty early on in his investigation and I made some movies of the stars using the NASA OpenSpace software we are co-developing at the American Museum of Natural History. Check out the video below that Berkeley released with the press summary of Kareem’s paper. It’s got two of the videos I made spliced together. The stars are not shown going around each other (but they definitely do!!!) because they would just zip in hard to detect circles since their orbital periods are much shorter than their motion through the Galaxy.