Are there stars that are not part of galaxies?

No, not all stars are in a galaxy. They may have once belonged to a galaxy, but they are not a part of it any more. Some of these so-called "stellar outcasts" or "intergalactic stars" have actually been observed by NASA's Hubble Space Telescope. read more

Answer: No, not all stars are in a galaxy. They may have once belonged to a galaxy, but they are not a part of it any more. Some of these so-called "stellar outcasts" or "intergalactic stars" have actually been observed by NASA's Hubble Space Telescope. read more

If you mean "are there stars that are not in any cluster or galaxy", then certainly there are. When two galaxies collide, they pass through each other, usually without any significant numbers of stars colliding (stars are very far apart!) but some stars get pulled out of their galaxies by gravitational forces as they pass, and they might pass through intergalactic space without ever striking a galaxy again. read more

Although stars normally reside within galaxies, they can be expelled by gravitational forces when galaxies collide. It is commonly believed that intergalactic stars may primarily have originated from extremely small galaxies, since it is easier for stars to escape a smaller galaxy's gravitational pull, than that of a large galaxy. read more