Characteristics of Stars

Star Definition Star – A body of gases consisting mainly of hydrogen and helium that gives off a tremendous amount of energy (electromagnetic radiation)  

Star Color – Depends upon surface temperature Blue stars – above 30,000 C White stars – 8,000 - 11,000 C Yellow stars – about 5,550 C (sun) Orange stars – about 4,000 C Red stars – about 3000 C  

Star Color

Star Size Vary from dwarf stars (size of the earth) to super giants that are 1000 times bigger than sun

Star sizes

Brightness of stars (magnitude) Absolute Magnitude – true brightness of a star – Depends upon temperature and size Apparent magnitude – brightness of a star as viewed from earth. Depends upon temperature, size, and distance to earth

Absolute magnitude

Classification of Stars – Hertzsprung-Russell (H-R) diagram – Comparison of absolute magnitude and temperature of stars. Main Sequence -most common star – (sun) Red Giants - very large, cool bright star Supergiants - extremely large bright star White dwarf – small, hot, dim star

H-R Diagram