Cecilia Payne- Gaposchkin A Woman of the Stars!

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By Pam Teel

Cecilia Payne-Gaposchkin, born Cecilia Helena Payne (May 1900 – December 7, 1979) was a British-born American astronomer and astrophysicist who proposed in her 1925 doctoral thesis that stars were composed primarily of hydrogen and helium. Her groundbreaking conclusion was initially rejected because it contradicted the scientific wisdom of the time, which held that there were no significant elemental differences between the Sun and Earth. Independent observations eventually proved she was correct. Her work on the nature of variable stars was foundational to modern astrophysics.

Payne was one of three children born in Buckinghamshire, England, to Prussian-born Emma Leonora Helena (née Pertz) and Edward John Payne, a London barrister, historian, and musician. Payne’s father died when she was four years old, forcing her mother to raise the family on her own.

Payne began her education at a private school. When she was twelve, her mother moved the family to London where Cecilia attended St Mary’s College in Paddington. There, she was unable to study much in the field of mathematics or science merely because she was a female. (Women were highly discouraged from studying these fields.) In 1918 she transferred to an all-girls school where she was urged to pursue a music career but preferred to focus on science.

Her mother refused to pay for her to go to college. The following year she won a scholarship that paid all her expenses at Newnham College, Cambridge University, where she focused on studying botany, physics, and chemistry.

Her interest in astronomy began after she attended a lecture by Arthur Eddington on his 1919 expedition to the island of Príncipe in the Gulf of Guinea off the west coast of Africa to observe and photograph the stars near a solar eclipse as a test of Albert Einstein’s general theory of relativity. She said of the lecture: “The result was a complete transformation of my world picture.”    She completed her studies but was not awarded a degree because she was a female. Cambridge did not grant degrees to women until 1948.

Payne realized that her only career option in the U.K. was to become a teacher, so she looked for grants that would enable her to move to the United States. In 1923, she was introduced to the Director of the Harvard College Observatory, Harlow Shapely.  He had just established a graduate program in astronomy, making it possible for women, with the aid of a fellowship, to study at the observatory. Payne became the second female student to benefit from the fellowship.  She was persuaded by Shapely to write a doctoral dissertation, and in 1925,  she became the first person to earn a Ph.D. in Astronomy from Radcliffe College of Harvard University.

Payne was able to accurately relate the spectral classes of stars to their actual temperatures by applying Indian physicist Meghnad Saha’s ionization theory. She showed that the great variation in stellar absorption lines was due to differing amounts of ionization at different temperatures, not to different amounts of elements. She found that silicon, carbon, and other common metals seen in the Sun’s spectrum were present in about the same relative amounts as on Earth, in agreement with the accepted belief of the time, which held that the stars had approximately the same elemental composition as the Earth. However, she found that helium and particularly hydrogen were vastly more abundant (for hydrogen, by a factor of about one million). Her thesis concluded that hydrogen was the overwhelming constituent of stars, making it the most abundant element in the Universe.

However, when Payne’s dissertation was reviewed, astronomer Henry Norris Russell dissuaded her from concluding that the composition of the Sun was predominantly hydrogen because it would contradict the scientific consensus of his 1914 article that the elemental composition of the Sun and the Earth were similar.

A few years later, astronomer Otto Struve described her work as “the most brilliant Ph.D. thesis ever written in astronomy”. Henry Norris Russell also realized that Payne was correct in her findings when he derived the same results by different means. In 1929, four years after Payne’s findings, Russell published his works in a paper that briefly acknowledged Payne’s earlier work and discovery, including the mention that, “the most important previous determination of the abundance of the elements by astrophysical means is that by Miss Payne.”  Nevertheless, he was generally credited for the conclusions she had reached four years earlier.

After her doctorate, Payne studied stars of high luminosity to understand the structure of the Milky Way. Later she surveyed all the stars brighter than the tenth magnitude. She then studied variable stars, making over 1,250,000 observations with her assistants. This work later was extended to the Magellanic Clouds, adding a further 2,000,000 observations of variable stars. These data were used to determine the paths of stellar evolution. She published her conclusions in her second book, The Stars of High Luminosity in 1930. Her observations and analysis of variable stars, along with her husband Sergei Gaposchkins analysis, laid the basis for all subsequent work on such objects.

Payne-Gaposchkin remained scientifically active throughout her life, spending her entire academic career at Harvard. When she began, women were barred from becoming professors at Harvard, so she spent years doing less prestigious, low-paid research jobs. Nevertheless, her work resulted in several published books, including The Stars of High Luminosity (1930), Variable Stars (1938), and Variable Stars and Galactic Structure (1954).

Harlow Shapely, the Director at Harvard, had made efforts to improve her position, and in 1938 she was given the title of “Astronomer.” On Payne’s request, her title was later changed to Phillips Astronomer, an endowed position that would make her an “officer of the university. To get approval for her title, Shapley assured the university that giving Payne-Gaposchkin this position would not make her equivalent to a professor but privately pushed for the position to be later converted into an explicit professorship as the “Phillips Professor of Astronomy.

She was elected a Fellow of the American Academy of Arts and Sciences in 1943. Her courses were not recorded in the Harvard University catalog until 1945.  Finally, in 1956, she became the first woman to be promoted to full professor from within the faculty at Harvard’s Faculty of Arts and Sciences. She was appointed the Phillips Professor of Astronomy in 1958. Later, with her appointment to the Chair of the Department of Astronomy, she also became the first woman to head a department at Harvard. Payne-Gaposchkin retired from active teaching in 1966 and was subsequently appointed Professor Emerita of Harvard. She continued her research as a member of staff at the Smithsonian Astrophysical Observatory, as well as editing the journals and books published by Harvard Observatory for ten years.

Since her death, the woman who discovered what the universe is made of has not so much as received a memorial plaque nor a mention in a high school book.  The complete lack of recognition Cecilia Payne gets, even today, for her revolutionary discovery is a blight on history. She should have been commended and recognized a long time ago for her astrological findings as well as for what she had to go up against to achieve as much as she did with so much prejudice against her. Not only did Cecilia Payne discover what the universe is made of, but she also discovered what the sun is made of, which led to her having to endure, for the rest of her life, someone else taking full credit for her findings.

Payne was a pioneer in her day. Women of her time looked up to her and this led to many generations of women choosing to study in a scientific field; a field that was once predominantly filled with only men. In tribute, thank you Cecilia Payne for your brilliance, your thorough study of the stars, and your contribution to the field of Astronomy!