NGC7635 · Bubble Nebula

Located approximately 7,100 light-years away in the constellation Cassiopeia, NGC 7635, better known as the Bubble Nebula, is one of the most remarkable emission nebulae in the northern sky. The striking bubble at the center of the image is not a solid object, but a gigantic cavity carved into the surrounding hydrogen cloud by the powerful stellar winds of the massive star BD+60°2522. These winds travel at several million kilometers per hour, compressing the surrounding gas and giving rise to the nebula's iconic spherical appearance. Although it appears relatively small, the bubble itself spans nearly 10 light-years across. It is embedded within a much larger region of gas and dust where new stars continue to form.