HR Diagram Characteristics of Stars TemperatureColor Mass Luminosity

HR Diagram

Characteristics of Stars ØTemperature/Color ØMass ØLuminosity • Absolute Magnitude • Apparent Magnitude

The Spectral Sequence O B Hottest 50, 000 K Bluest A F G K M L Coolest 1300 K Reddest Oh Boy, an F grade kills me, Louis!

The mass of a star determines the length of its life cycle (how long will it burn).

Sun-like Stars Up to 1. 5 times the mass of the Sun

Huge Star From 1. 5 to 3 times the mass of the Sun

Giant Star Over 3 times the mass of the Sun

Sun/main sequence star Stellar Nebula Red Giant Planetary Nebula Protostar (nursery) Massive Star Neutron Star ( Huge & Giant) Red Supergiant Supernova Black Hole White Dwarf

Variables which affect a star’s brightness: ØStar size ØDistance from Earth ØStar temperature

Absolute Magnitude vs. Apparent Magnitude • Actual Brightness: How • Apparent Brightness: large and hot a star is in The amount of light relation to other stars. received on Earth from a star.

Which star looks like it is giving off more light? • But, which star is actually giving off more light?

Luminous/Brighter Stars Dim Stars Hotter Stars Cooler Stars

O B A F G K M

• Life Cycle of Stars Interactive Investigation http: //aspire. cosmic-ray. org/labs/star_life/starlife_main. html • HR Diagram Interacative Lab http: //aspire. cosmic-ray. org/labs/star_life/hr_interactive. html • Stellar Evolution/H-R Diagram Simulation http: //instruct 1. cit. cornell. edu/courses/astro 101/java/evolve. htm • Astronomy Place Tutorials http: //media. pearsoncmg. com/bc/bc_bennett_cosmicpers_2/medialib/tutorials/inde x. html