Characteristics of Stars 4-2

Constellations Today we use constellations to find stars in the night sky.

Classifying Stars Color Temperature Size Composition Brightness

Star Temperature Surface Temperature = Color Blue-white White yellow orange red Hottest *Sun coolest

Compare the sizes of Stars Our Sun is a medium sized Star

What is a Star? Hot glowing masses of Gases Composition: Mostly Hydrogen and Helium

What makes a Star Shine? The fusion of Atoms Hydrogen atoms fusing to form Helium releasing Heat, Light and energy Astronomers use a Spectroscope to determine the composition of a Star

Star Brightness (magnitude) Absolute Magnitude: the “Real” brightness of the star. How much light it really gives off.(Need to know the distance to the Star) Apparent Magnitude: How bright the star appears to be.

Star Distance Measured in Light-Years Light-Year: The distance light travels in a year. (9.5 million million Kilometers) × miles (6 trillion miles) Speed of light: 186,000 Miles/second 300,000 Kilometers/Second

Finding the Distance to Stars Parallax: The “apparent “ Shift that a star has over a period of Time The closer the object, the more it will shift position in the sky * Background Star

H-R Diagram Hertzsprung-Russell Compares star temperature and Brightness

Star Types