| A | B |
|---|
| BLACK HOLE | a massive collapsed star whose gravity field is so strong that light can not escape |
| BLUE STARS | the hottest stars |
| FIRST STAGE | during this stage of the star’s life cycle, the star is a ball of gas and dust |
| FUSION | the process in which hydrogen is converted into helium |
| GRAVITY | keeps a star from breaking apart |
| H R DIAGRAM | a graph that shows the relationship between temperature & brightness |
| HYDROGEN | changes into helium as a star becomes hotter |
| MAIN SEQUENCE | longest stage on a star’s life cycle |
| NEBULA | a cloud of gas and dust in space |
| NEUTRON STAR | all the particles in this star are neutrons |
| NOVA | an explosion of a medium star |
| PULSAR | spinning neutron star that emits bursts of energy |
| RED DWARF | a small cool star |
| RED GIANT | expanded cool stars: the next stage in the life of our sun |
| RED SUPERGIANT | a huge star that has run out of hydrogen at its core |
| RELATIVE BRIGHTNESS | this quantity is plotted on the y-axis of the H R Diagram |
| SUPERNOVA | a gigantic explosion in which a massive star expands and then collapses |
| TEMPERATURE | this quantity is plotted on the x-axis of the H R Diagram |
| WHITE DWARF | small hot stars that are the leftover centers of old stars |
