(astronomy) the magnitude that a star would have if it were viewed from a distance of 10 parsecs (32.62 light years) from the earth
Inverse Square Law
gravitational force varies inversely with the square of the distance between two objects
Hertzsprung-Russell diagram, a graph that shows the relationship between a star's surface temperature and absolute magnitude
Gases (mainly hydrogen and helium) and dust grains (silicates, carbon and iron) filling the space in between stars. The density of interstellar mass is very low. There is about one atom of gas in every cubic centimeter of space. The density of dust is a trillion times smaller. The temperature of the gas is about 100 K.
the changes in size, luminosity, temperature, and chemical composition that occur as a star ages
An expanding shell of gas ejected at high speeds by a supernova explosion. Supernova remnants are often visible as diffuse gaseous nebulae usually with a shell-like structure. Many resemble "bubbles" in space.
a star that ejects some of its material in the form of a cloud and become more luminous in the process