Early stars of less than 2 M ☉ are called T Tauri stars , while those with greater mass are Herbig Ae / Be stars . These newly formed stars emit jets of gas along their axis of rotation , which may reduce the angular momentum of the collapsing star and result in small patches of nebulosity known as Herbig – Haro objects . These jets , in combination with radiation from nearby massive stars , may help to drive away the surrounding cloud from which the star was formed .