Fiona Ward Emily Linden

“Explain the usefulness of classifying stars according to their colors, surface temperatures, and spectral characteristics.” THE QUESTION

Color and Blackbody Curve Determines surface temperature Works for any star regardless of distance Color Index + Photometry + Stellar Spectra = Color = Temperature COLORS This slide: Astronomy Today textbook

Temperature + Color = Composition The biggest and brightest stars are the hottest. Some can grow to be 100 times bigger than our Sun. Color + Temperature = Length of life Blue and white are the brightest Yellow stars last 10 billion years Red stars last longer It then turns into a super giant or red giant. TEMPERATURES This slide:

This picture: ALL THREE

( ) Originally measured by Hydrogen-line Intensities A – P (1920s) Development of Atomic Theory Reclassification by Surface Temperature O B A F G K M SPECTRAL CHARACTERISTICS This slide: Astronomy Today textbook This picture:

Classifying stars according to color, temperature, and spectral classifications:  Explains Our Universe  Determines the Building Blocks of the Solar System  Determines the Life of Stars Determines our Eminent Doom THE ANSWER