In the well well known Keyhole Nebula (NGC 3372) surrounding the super-star Eta Carinae is an interesting feature that some astronomers have labeled the "Rude Gesture Nebula".

Since it is several hundred light years away, it is huge- light-years across. It is a gas and dust cloud in which new stars are forming. The odd shapes were created by the hot solar winds and radiation pressures created by the massive young stars in this stellar nursery.

Super-stars like Eta Carinae, or stars with a mass 100 times that of the sun, are quite rare. They account for less than 1% of all stars but 60% of all luminosity in the universe. They live very short lives in astronomical terms, 10s of millions of years, before they explode and enrich the surrounding cosmos with dust and gas for the next generation of stars.

Most stars are much more mundane. They are even smaller than our own sun but what they give up in mass, they gain in longevity. Main sequence stars like our Sun and smaller are quite stable and last for billions of years.

The smallest known stars are about 1/10 of our own sun's mass. This is also about the same size as some of the larger "brown dwarfs" or Jupiter like gas giants or "pre-stars". This begs an interesting question which vexes astronomers and physicist: what causes some brown dwarfs to ignite and become true stars and what causes others to just sit there?