Sci. 4-2 The life Cycle of StarsPages 105-109

A. New stars form from the material of old stars that have gone through their life cycles.

B. Hertzsprung- Russell or H-R Diagram- a graph showing the relationship between star’s surface temperature and its absolute magnitude.

1) H-R diagram relates the temperature and brightness of stars. It also illustrates the life cycle of stars.

http://www.youtube.com/watch?v=HfqcZdNnQ6s

C. Main Sequence- a diagonal pattern of stars on the H-R diagram. 1) Small mass stars are found at the right end. 2) As main sequence stars age, they move up and to

the right on the H-R diagram to become giants and supergiants.

D. Most stars are main sequence stars. Red giants and white dwarfs are later stages in a star’s life cycle.

E. Blue stars may explode in a tremendous flash of light called a supernova.

1) Supernova- basically the death of a large star by explosion.

2) Silver, gold, and lead are formed by supernova.

F. Neutron Star- a star in which all the particles have become neutrons, the collapsed remains of a supernova.

G. Pulsars- spinning neutron stars

H. Black Holes- an object with more than three solar masses squeezed into a ball only 10 km across whose gravity is so strong that not even light can escape.