Describing and Measuring Stars

Who helped establish the modern system of stellar spectral types?

A number of astronomers, over many years, worked to create a scientifically sensible classification system for spectral types. The three astronomers who were probably most influential in establishing the OBAFGKM sequence were Williamina Flem ing (1857–1911), Antonia Maury (1866–1952), and Annie Jump Cannon (1863–1941). The order of the letters in the spectral sequence came about because there were originally more than seven types, and because the types were first identified in ways other than the colors of stars. To avoid confusion, these astronomers decided to move the order of the types around to make scientific sense, instead of creating brand-new types. Although unusual, the letter order stuck, and the system is still being used today—more than a century after its establishment.


This is a web preview of the "The Handy Astronomy Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App