The woman who knew what stars were made of

In 2008, the IOP introduced the Cecilia Payne-Gaposchkin Medal and Prize for distinguished contributions to plasma, solar or space physics. The medal is named in honour of the brilliant but marginalised astronomer who discovered that stars are formed largely of hydrogen and helium.

Payne-Gaposchkin showed an early aptitude for experimental science, carrying out a controlled trial on the impact of prayer on her exam results at Sunday school: she reported that she obtained better results in exams when she had not prayed for success.

As a child, she was also a talented musician and was encouraged by her school music teacher, Gustav Holst, composer of The Planets Suite, to pursue a musical career.

Fortunately for the development of astrophysics, Payne-Gaposchkin chose to study science at Cambridge University. Whilst there, she reported the impact of getting one of only four tickets to attend a lecture by Eddington on his expedition to test Einstein’s theory of relativity:

The result was a complete transformation of my world picture… When I returned to my room I found that l could write down the lecture word for word (as l was to do for another lecture a couple of years later). For three nights, I think, I did not sleep. My world had been so shaken that I experienced something very like a nervous breakdown.

Payne-Gaposchkin moved to the United States and undertook research for a PhD on the spectra of stars. At the time, it was believed stars were composed of a similar mix of elements to the Earth, but her research showed this belief was mistaken, instead showing that hydrogen and helium were the most abundant constituent elements.

After reading her thesis, the eminent but orthodox astronomer Henry Norris Russell (of the eponymous diagram) encouraged Payne-Gaposchkin to drop her conclusion. In 1925, Payne-Gaposchkin published her ground-breaking finding in her thesis, down-playing it by writing: “The enormous abundances derived for those elements in the stellar atmosphere are almost certainly not real.”

Decades later, Russell reached the same conclusions as Payne- Gaposchkin and acknowledged her work. Her thesis has since been described as “the most brilliant PhD thesis ever written in astronomy”.