This week, the stars of Eta Carinae made their closest approach — about the distance between Mars & the Sun — to each other occurring every 5.5 years. As the most massive, radiant & unstable star system within 10,000 light-years, it could even be the next bright supernova. 
The larger of the two stars in Eta Carinae is a luminous blue variable about 90 times the mass of our Sun. Though rare now, we think these “superstars” were common in the early universe, when they were fundamental in forming the first black holes.
The smaller star (about 30 times the mass of the Sun) is outshone by its larger companion making it tough to directly detect. But it has found a way to make itself known! Its stellar wind collides with the wind of its comrade which creates very hot gas and a strong X-ray signal.
Our @chandraxray, Fermi, Swift, NuSTAR & NICER detect X-rays & gamma rays from Eta Carinae. These data, combined with @NASAHubble images & models, help us characterize the orbits, understand the stellar winds, & see how wind collisions speed up particles. go.nasa.gov/2V9eFgq
