Starbirth. Animation showing the birth of a star. Stars form from the gravitational collapse of a cloud of gas and dust. Infalling material coalesces under its own gravity until temperatures are high enough for nuclear reactions to begin. The infalling material spirals onto the new star, and bipolar jets erupt from its poles to balance angular momentum. At this stage the star is known as a T Tauri star, after the prototype star of the class. The jets collide with material surrounding the star, heating them and causing them to glow, forming a system called a Herbig_Haro object HH object. This system is pictured in the Orion Nebula, a huge starbirth region some 1500 light years from Earth.