The Color of Stars: Uses of Stellar Color in the Long 19th Century

Abstract

Although many stars appear to twinkle with a soft white light, they can actually have a wide range of colors. From the golden yellow of our Sun, to the variable blues and oranges of binaries, to the red tint of distant stars, this color is a powerful tool that can teach us a great deal. In this thesis, I explore investigations of stellar color in the long 19th century (1802-1914). In each chapter, I focus on one physical characteristic of a star that color can be used to learn about: composition, motion, and temperature. For each of these instances, I examine the way in which color came to be understood as an indicator of that property. These histories were complex: the contemporary astrophysical understanding of the meaning of stellar color is based upon a combination of multiple paths that arose in different disciplines. In order to study this history, I look at papers written by scientists from this time period (a time period in which conceptions of color and of the stars were fundamentally shifting). Examining their writing allows for an insight into the process of doing science – an insight which has the ability to inform the way science is practiced today.