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Homo Resiliens @mekonto.qoto.org.ap.brid.gy · 10/05/2025

In honor of the 125th anniversary of her birth, read this article about Cecilia H. Payne Gaposchkin, the woman who discovered what the stars are made of womeninastronomy.blogspot.com/2025/…

womeninastronomy.blogspot.com

Women Reinventing Science - Part 3

Eds Note: We’re delighted to share with our readers excerpts from The Reinvention of Science by Bernard Jones, Vicent Martínez and Virginia Trimble, which describes women scientists who helped reinvent science. To learn about the book, watch a video summary. In honor of the 125th anniversary of the birth of Cecilia Payne-Gaposchkin (May 10, 1900), please enjoy the below excerpted text. By Vicent J. Martínez, Professor of Astronomy and Astrophysics at the Universitat de València --- C. Payne-Gaposchkin (1900-1979). Image Credit: broadway-stages.com To Cambridge, Harvard University, came in 1923 Cecilia Helena Payne (1900–1979), fresh from the Cambridge (UK) influence of Arthur Stanley Eddington (a strong believer in uniformity) and from the labs of Ernest Rutherford. She carried with her an understanding of the beginning of quantum mechanics, in particular the idea of Meghnad N. Saha (1893–1956) that the fraction of atoms of a particular element that would have electrons in the right orbits to absorb particular wavelengths of light would be a (quite steep) function of the temperature of the gas. She also had just enough fellowship money to enable her to choose her own research topic, looking toward a doctorate. She chose to make use of some of the enormous number of spectrograms of stars of different colors, hence having different temperatures, sitting in the Harvard plate vaults. Payne wrote up her work and shared the draft with her advisor, Harlow Shapley, director of the Harvard College Observatory. He (and everyone else quickly) said, indeed all stars have the same chemical composition, and it is like the Sun and Earth, except that dominance of helium and hydrogen. That cannot be right, he said. Shapley shared the draft with Russell, who was to be her external examiner. Yes, said Russell, magnificent, indeed the best astronomy thesis I’ve seen except for Shapley’s. But the dominance of H and He cannot be right. She should say it is somehow spurious. The thesis was modified accordingly (and later she said she very much regretted having to do so, but it was politically the only possible choice). Thus, in 1927 H.N. Russell, R.D. Dugan, and J.Q. Stewart, in their classic text Astronomy could write that _Miss Payne_[though her PhD had come in 1925]_had shown that the gas pressure was low in stellar atmospheres, that the hottest stars had surface temperatures up at least to 35,000 K_ , and that _the uniformity of composition of stellar atmospheres appears to be an established fact._ But the behavior of hydrogen, helium, and to a lesser extent of oxygen was “puzzling.” Staying on at Harvard, Payne became Shapley’s employee badly underpaid compared to men doing the same jobs and required to devote more and more of her attention not to further analysis and interpretation of stellar spectra (where her heart lay) but to the establishment of brightness standards for stars recorded as images on photographic plates and to studying the variable brightness of Cepheids and other pulsating variables, novae and all. Eddington, whom she had adored from afar beginning in 1919, when she returned to England post-PhD said, “not in the stars; on the stars,” and indeed some chemical separation was part of the story, but the main plot line was and is that the stars, galaxies, interstellar and intergalactic stuff are made mostly of hydrogen and helium (left from the hot, dense early phase of the universe that we call the Big Bang). Decades later, Otto Struve (Russian–American, 1897–1963) and last of a long familial line of astronomers, over the years President of the American Astronomical Society, the International Astronomical Union, and editor of the Astrophysical Journal while director of Yerkes Observatory declared that Payne had written the most important astronomical thesis of the century. Payne married Russian refugee astronomer Sergei Illarionov Gaposchkin in 1934, and much of the variable star work was done with him (she is generally thought to have done most of the real work). Recognition came slow and late. She was finally appointed to a Harvard professorship in 1956 (but retired with a salary still considerably less than those of men with less seniority). The highest honor of the American Astronomical Society is the Russell lecture. He gave the first one in 1946, Shapley the 4th in 1950, Struve the 10th in 1957, and Payne-Gaposchkin the 29th in 1976, the first woman to do so, and with the first-ever female president of the American Astronomical Society, E. Margaret Burbidge to introduce her. Burbidge herself became the 37th Russell lecturer and second woman in 1984. Born in Wendover, England, in 1900, Cecilia Helena Payne- Gaposchkin, a life-long heavy smoker, died of lung cancer in Massachusetts on 7 December 1979. Learn more! * This Astronomer Discovered What the Stars Were Made Of, and Few Believed Her Discovery * Cecilia Payne-Gaposchkin and the Day the Universe Changed * Cecilia Payne and the Composition of the Stars

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