Stars Glossary

chromosphere: A hot outer layer present in many stars, lying between the photosphere and the corona.

convection: The rising of heated material and falling of cooled material in a region simultaneously heated from below and cooled from above, such as a pot of water about to boil or the interior of a star.

convective zone: A layer of a star, where convection occurs, producing turbulence. This turbulence generates the Sun’s magnetic field.

core: The center of a star, where nuclear fusion generates intense energy.

corona: The million-degree outermost layer of many stars, which is so hot that gas escapes the star’s gravity and flows out into space as a stellar wind.

gravity: The force of attraction between any two masses.

heliosphere: The extent of space effected by the Sun's magnetic field, which reaches past Pluto.

hydrostatic equilibrium: In a star, the balance achieved between the enormous outward pressure of gas heated by fusion and the inward pull of its own gravity.

luminosity: The total amount of light that a star emits. Luminosity is not the same as brightness, which drops off with distance.

magnetic field: The force produced by moving, charged material, such as the turbulent, ionzed gas in a star's convective zone.

mass: The amount of matter contained within a given object.

neutron star: A stellar remnant formed by a massive star when it explodes as a super nova at the end of its life. 

nuclear fusion: The combination of light atoms such as hydrogen and helium into heavier ones, such as helium, carbon, and oxygen. This process releases intense energy.

radiation: Energy that travels in the form of rays or waves (e.g. electromagnetic waves such as light, radio, X-rays, and gamma rays), or in the form of subatomic particles.

solar flare: A magnetic explosion on the Sun that produces storms in the solar wind and generates dangerous radiation.

stellar wind: A flow of high-speed gas ejected by stars. It is call the solar wind when referring to our Sun.