How many known stars are part of a binary or multiple stars system?The majority of stars in the galaxy are part of binary or multiple star systems. According to some estimates, up to 80% of stars in the Milky Way may be part of binary or multiple systems.
There are many different types of binary and multiple star systems, ranging from close binary systems where the two stars orbit very close to each other, to wide binary systems where the stars are separated by a significant distance. There are also hierarchical systems, where multiple stars orbit around a common center of mass, and even more complex systems with multiple stars and planets.
The exact number of known binary and multiple star systems is difficult to determine, as new systems are constantly being discovered through observations and research. However, as of 2021, the latest estimate from the European Space Agency's Gaia mission is that there are approximately 100 billion stars in the Milky Way, and the majority of these are likely to be part of binary or multiple systems.
