Stars Study Guide

Study Guide Bi r th - Stars are born in the nebula, which are huge clouds of gas and dust. The nebula begins to contract under the pull of its own gravity. This forms a protostar.

Main Sequence Star - Stars live out the majority of their lives in a phase termed as the Main Sequence. This is the longest, most stable period of a star’s life. It converts hydrogen to helium in its core, generating heat and light.

Red Giants and Supergiants - As the nuclear fuel becomes depleted the core contracts and our layers expand.

Planeta ry Nebula - Now the outer layers of the star start to drift off into space. The star loses most of its mass to the nebula.

White D wa rf - The star cools and shrinks. No nuclear reactions take place and the faint star radiates it heat into space.

Black D wa rf - The star will eventually lose all its heat and energy and become dark and cold.

Supernova - The core collapses in an instant. Forces in the core overcome the gravitational forces, causing a massive, short-lived explosion.

Neutron Star - It contracts into a small star that has extraordinarily strong magnetic field, and a rapid spin.

Black Hole - It contracts and becomes a black hole. The gravitational field is so strong that even light cannot escape.

H-R Diagram - The Hertzsprung-Russell Diagram is a graphical tool that astronomers use to classify stars according to their luminosity, spectral type, color, temperature and evolutionary stage.

Spiral Galaxy – Spiral galaxies have a curved bulge in the center that is surrounded by distinct, revoloving arms. The milky way, the galaxy earth belongs to, is spiral.

Elliptical Galaxy – Elliptical galaxies are massive blobs of stars. Some are spherical in shape, while others are more oval. Elliptical galaxies contain old stars so they are the oldest type of galaxy in the universe.

I r regular Galaxy – Irregular galaxies that do not belong in the spiral galaxy or elliptical galaxy categories. Many irregular galaxies look simply like clouds of stars and nebulas.

Sun (Small or medium) Size Star - Sun  Red Giants  Planetary Nebula  White Dwarf  Black Dwarf  H uge Sta rs - Huge Star  Red Supergiant  Supernova  Neutron star Giant Stars - Giant Star  Red Supergiant  Supernova  Black Hole