Galactic Star Clusters

Stars form in giant molecular clouds containing gas and dust. Dozens to thousands of stars can form from an individual cloud. When the stars have all formed, their combined solar winds disperse the remaining cloud. What is left over is called a galactic star cluster or an open star cluster. In a spiral galaxy like the Milky Way, these star-forming regions and thus open star clusters are typically found in the plane of the galaxy within the spiral arms. Massive stars form much faster than yellow dwarf stars like the Sun. Likewise, stars much more massive than the Sun burn through their supply of nuclear fuel much faster and have short lifetimes. Red dwarf stars have only 10% the mass of the Sun. They take longer to form but may live one hundred times longer than the Sun. While red dwarf stars are not as bright as yellow dwarf stars, giant stars, and supergiant stars, most of the stars in the universe may be red dwarf stars.