A group of stars that form when lots of gases and dust come together is called a nebula.

Here's why:

* Nebula: A nebula is a giant cloud of gas and dust in space. These clouds can be incredibly vast, spanning many light-years.

* Star Formation: Within nebulae, gravity pulls the gas and dust particles together. As the cloud collapses, it becomes denser and hotter. Eventually, the core of the collapsing cloud becomes hot and dense enough to ignite nuclear fusion, which is the process that powers stars.

* Star Clusters: Often, multiple stars form within a single nebula, leading to the formation of star clusters.

So, while nebulae are the birthplace of stars, they themselves are not a group of stars. They are the raw material from which stars are formed.