* We can only observe a limited portion of the galaxy: Our telescopes can only see a small fraction of the stars in our galaxy, and even fewer in other galaxies.
* Double and triple star systems are difficult to detect: Many are too far away to be resolved as separate stars, and even when they are, the stars can be faint and their orbits difficult to observe.
* The definition of "double star" is somewhat fuzzy: Some stars are gravitationally bound pairs, while others just appear close together from our perspective.
However, we do know that:
* Double and triple star systems are relatively common: Studies suggest that roughly half of all stars are part of multiple star systems.
* More massive stars are more likely to be in multiple star systems: This is likely due to how stars form in clusters, with the more massive stars having a greater chance of encountering other stars and forming multiple systems.
So, while we don't have a precise number, it's fair to say that a significant portion of the stars in the universe are part of double or triple star systems.
