Cecilia Payne (1900–1979)

Cecilia Payne (1900–1979) was a British-born American astronomer and astrophysicist. She was the first to discover that stars were composed primarily of hydrogen and helium. When her mother refused to fund her college education, she applied for and received a scholarship at Cambridge College. Even though Cecilia completed her studies at Cambridge, she was refused a degree because she was a woman.

Photographic image of Cecila Payne
Cecilia Payne

Cecilia decided to leave England for the United States to accept a graduate fellowship from Harlow Shapley, the new director of the Harvard College Observatory. At the time, Harvard was renowned for its comprehensive study of stellar spectrum. Cecilia earned her Ph.D. (~1925) in astronomy from Radcliffe College and her thesis was described by Otto Strauve, (Russian-American astronomer), as “the most brilliant Ph.D. thesis ever written in astronomy.”

Her thesis involved measuring the absorption lines in stellar spectra, “…she showed that the wide variation in stellar spectra is due mainly to the different ionization states of the atoms and hence different surface temperatures of the stars, not to different amounts of the elements. She calculated the relative amounts of eighteen elements and showed that the compositions were nearly the same among the different kinds of stars. She discovered, surprisingly, that the Sun and the other stars are composed almost entirely of hydrogen and helium, the two lightest elements. All the heavier elements, like those making up the bulk of the Earth, account for less than two percent of the mass of the stars.”1

Later, she converted her thesis into a book titled “Stellar Atmospheres.”

In 1934 she married the Russian astronomer Sergei Gaposchkin. Their professional collaboration contributed widely to the physical understanding of the chemical elements in the stars.

Although it took until 1956, Cecilia Payne became the first woman to be promoted to full professor from within Harvard, and is often credited with breaking the glass ceiling for women in the Harvard science department and in astronomy, as well as inspiring entire generations of women to take up science.

Bibliography:

1Cosmic Horizons: Astronomy at the Cutting Edge, edited by Steven Soter and Neil deGrasse Tyson, a publication of the New Press. © 2000 American Museum of Natural History. (https://www.amnh.org/learn-teach/curriculum-collections/cosmic-horizons-...)

https://en.wikipedia.org/wiki/Cecilia_Payne-Gaposchkin