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British-American astronomer (1900–1979) From Wikipedia, the free encyclopedia
Cecilia Payne-Gaposchkin (born Cecilia Helena Payne; May 10, 1900 – December 7, 1979) was a British-American astronomer and astrophysicist. In her 1925 doctoral thesis she proposed that stars were composed primarily of hydrogen and helium.[1] Her groundbreaking conclusion was initially rejected by leading astrophysicists, including Henry Norris Russell,[2] because it contradicted the science of the time, which held that no significant elemental differences distinguished the Sun and Earth. Independent observations eventually proved that she was correct.[1][2][3][4]
Cecilia Payne-Gaposchkin | |
|---|---|
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| Born | Cecilia Helena Payne May 10, 1900 Wendover, Buckinghamshire, England |
| Died | December 7, 1979 (aged 79) Cambridge, Massachusetts, U.S. |
| Citizenship | British United States (from 1931) |
| Education | St Paul's Girls' School |
| Alma mater | Newnham College, Cambridge; Harvard University |
| Known for | Explanation of stellar spectra and composition of the Sun, more than 3,000,000 observations of variable stars |
| Spouse |
Sergei I. Gaposchkin
(m. 1934) |
| Children | 3 |
| Awards | Annie Jump Cannon Award in Astronomy (1934), Rittenhouse Medal (1961), Award of Merit from Radcliffe College (1952), Henry Norris Russell Prize (1976) |
| Scientific career | |
| Fields | Astronomy, astrophysics |
| Institutions | Harvard College Observatory, Harvard University |
| Thesis | Stellar Atmospheres: A contribution to the observational study of high temperature in the reversing layers of stars (1925) |
| Doctoral advisor | Harlow Shapley |
| Doctoral students | Helen Sawyer Hogg, Joseph Ashbrook, Frank Kameny, Frank Drake, Paul W. Hodge |
| Signature | |
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Overcoming barriers for female scientists – Payne did not receive a degree from Cambridge despite completing her studies[5] – her work on the cosmic makeup of the universe and the nature of variable stars was foundational to modern astrophysics. She was elected to the Royal Astronomical Society while still a student at Cambridge[6] and later became the first recipient of the American Astronomical Society’s prestigious Annie J. Cannon award.[7] Her success also opened the door for countless female astronomers, including her Harvard colleague, Helen Sawyer Hogg,[8] and in 1956, she was appointed Harvard’s first female Professor and female Department Chair.[9]
Cecilia Helena Payne, born in Wendover in Buckinghamshire, England,[10] was one of three children to Emma Leonora Helena (née Pertz) and Edward John Payne, a London barrister, historian and musician who had been an Oxford fellow.[11] Her mother came from a Prussian family and had two distinguished uncles, historian Georg Heinrich Pertz and the Swedenborgian writer James John Garth Wilkinson.[12] When Cecilia was four, her father died, leaving her mother to raise the family on her own.
Payne began her formal education in Wendover at a private school run by Elizabeth Edwards.[13] When Payne was twelve, her family moved to London to support her brother Humfry's education; he later became an archaeologist. Payne initially attended St Mary's College, Paddington, where she was unable to study much mathematics or science. In 1918, she transferred to St Paul's Girls' School, where her music teacher, Gustav Holst, encouraged her to pursue a career in music. However, Payne decided to focus on science. The following year she won a scholarship covering her expenses at Newnham College, Cambridge University, where she studied physics and chemistry.[11]
Her interest in astronomy began after she attended a lecture by Arthur Eddington, detailing 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.[14] She said of the lecture: "The result was a complete transformation of my world picture. [...] My world had been so shaken that I experienced something very like a nervous breakdown."[15]: 117 Although she completed her studies, she did not receive an official degree, because Cambridge did not grant degrees to women until 1948.[16]
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. LJ (Leslie John) Comrie, an astronomy PhD candidate at Cambridge University, introduced her to Harlow Shapley, the Director of the Harvard College Observatory, after a lecture in London at the British Astronomical Association.[5][14][17] In 1923, Payne moved to the United States to study at Harvard College, enabled by a fellowship established to encourage women to study at the Harvard Observatory. Adelaide Ames had been the first recipient of this fellowship in 1922, with Payne following as the second. Lawrence H. Aller later described Payne as one of the "most capable go-getters" in Shapley's observatory.[18]
Shapley persuaded Payne to write a doctoral dissertation, and so in 1925 she became the first person to earn a PhD in astronomy from Radcliffe College of Harvard University.[14][19] Her thesis title was Stellar Atmospheres; A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars.[1][20]
While analyzing glass plates at the Harvard College Observatory,[5] Payne made a groundbreaking discovery by accurately relating the spectral classes of stars to their actual temperatures using Indian physicist Meghnad Saha's ionization theory. She demonstrated that the great variation in stellar absorption lines was due to differing amounts of ionization at different temperatures, not to varying amounts of elements. Payne found that silicon, carbon, and several common metals seen in the Sun's spectrum were present in about the same relative amounts as on Earth, which aligned with the prevailing belief that stars had a similar elemental composition as on Earth. However, she also found that helium, and particularly hydrogen, were vastly more abundant in stars, with hydrogen being about a million times more prevalent, leading her to conclude that hydrogen was the overwhelming constituent of stars, making it the most abundant element in the Universe.[21][22]
However, when Payne's dissertation was reviewed, Henry Norris Russell, a pre-eminent astronomer of the day who adhered to the theories of American physicist Henry Rowland, urged her not to assert that the composition of the Sun was predominantly hydrogen because it contradicted the scientific consensus of the time that the elemental composition of the Sun and the Earth were similar.[23] Russell, in a 1914 article, had argued that:
The agreement of the solar and terrestrial lists is such as to confirm very strongly Rowland's opinion that, if the Earth's crust should be raised to the temperature of the Sun's atmosphere, it would give a very similar absorption spectrum. The spectra of the Sun and other stars were similar, so it appeared that the relative abundance of elements in the universe was like that in Earth's crust.[24]
Consequently, Russell described her results as "spurious".[20]: 186 [22] Although she included all calculations and results, Payne agreed to write in her thesis that her results were "almost certainly not real."[5]
Four years later, however, Russell realized that Payne had been correct when he derived the same results by different means, effectively demonstrating that hydrogen and helium were the most abundant elements in the Milky Way. Sharing his results in 1929, Russell briefly acknowledged Payne's earlier work and discovery, including the mention that "[t]he most important previous determination of the abundance of the elements by astrophysical means is that by Miss Payne [...]".[25] Nevertheless, Russell was generally credited for the conclusions she had reached four years prior.[25][26]
Nearly 40 years after Payne's thesis was published, astronomer Otto Struve described her work as "the most brilliant PhD thesis ever written in astronomy".[2][27] Today's accepted ratios for hydrogen and helium in the Milky Way Galaxy are ~74% hydrogen and ~24% helium, confirming the results of Payne-Gaposchkin's calculations from 1925.[28]
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After earning her doctorate in 1925, Payne remained at Harvard for the entirety of her academic career. Initially, women were barred from becoming professors at Harvard, so she spent years doing less prestigious, low-paid research jobs. Her early work focused on stars of high luminosity to understand the structure of the Milky Way. Later she surveyed all 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 (1930).[21] On a tour through Europe in 1933, Payne met Russian-born astrophysicist Sergei I. Gaposchkin in Germany. She helped him obtain a visa to the United States, where they married in March 1934.[5] Her observations and analysis of variable stars, carried out with Sergei Gaposchkin, laid the basis for all subsequent work on such objects.[1]
Her work resulted in several published books, including The Stars of High Luminosity (1930), Variable Stars (1938) and Variable Stars and Galactic Structure (1954). Shapley (the Director of the Harvard College Observatory) 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 which would make her an "officer of the university"; in order 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".[15]: 225 [29][30] She was elected a Fellow of the American Academy of Arts and Sciences in 1943.[31] Her courses were not recorded in the Harvard University catalogue until 1945.[1]
When Donald Menzel became Director of the Harvard College Observatory in 1954, he tried to improve her appointment, and 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.[14] She was appointed the Phillips Professor of Astronomy in 1958.[30] Later, with her appointment to the Chair of the Department of Astronomy, she also became the first woman to head a department at Harvard.[14]
Her students included Joseph Ashbrook, Frank Drake, Harlan Smith and Paul W. Hodge, all of whom made important contributions to astronomy.[32] She also supervised Helen Sawyer Hogg, Frank Kameny[33] and Owen Gingerich.[34]
Payne-Gaposchkin retired from active teaching in 1966 and was subsequently appointed Professor Emerita of Harvard.[3] 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.[35] She edited and published the lectures of Walter Baade as Evolution of Stars and Galaxies (1963).[36]
Payne-Gaposchkin's career marked a turning point at Harvard College Observatory. Under the direction of Harlow Shapley and Dr. E. J. Sheridan (whom Payne-Gaposchkin described as a mentor[15]), the observatory had already offered more opportunities in astronomy to women than did other institutions. This was evident in the achievements accomplished earlier in the century by Williamina Fleming, Antonia Maury, Annie Jump Cannon, and Henrietta Swan Leavitt. However, with Payne's PhD, women entered the mainstream.[37]
The trail she blazed into the largely male-dominated scientific community was an inspiration to many. For example, she became a role model for astrophysicist Joan Feynman. Feynman's mother and grandmother had dissuaded her from pursuing science, since they believed women were not physically capable of understanding scientific concepts.[38][39][40] Feynman was inspired by Payne-Gaposchkin when she came across her work in an astronomy textbook. Seeing Payne-Gaposchkin's published research convinced Feynman that she could, in fact, follow her scientific passions.[38]
While accepting the Henry Norris Russell Prize from the American Astronomical Society, Payne spoke of her lifelong passion for research: "The reward of the young scientist is the emotional thrill of being the first person in the history of the world to see something or understand something. Nothing can compare with that experience [...] The reward of the old scientist is the sense of having seen a vague sketch grow into a masterly landscape."[41]
In her autobiography, Payne said that while in school she created an experiment on the efficacy of prayer by dividing her exams in two groups, praying for success only on one, the other one being a control group. She achieved the higher marks in the latter group.[15]: 97 Later on, she became an agnostic.[42]
In 1931, Payne became a United States citizen, so held joint citizenship of both the UK and the US. On a tour through Europe in 1933, she met Russian-born astrophysicist Sergei I. Gaposchkin in Germany. She helped him get a visa to the United States, and they married in March 1934, settling in the historic town of Lexington, Massachusetts, a short commute from Harvard. Payne added her husband's name to her own, and the Payne-Gaposchkins had three children: Edward, Katherine, and Peter. Payne's daughter remembers her as "an inspired seamstress, an inventive knitter, and a voracious reader". Payne and her family were members of the First Unitarian Church in Lexington, where Cecilia taught Sunday school. She was also active with the Quakers.[43] She died at her home in Cambridge, Massachusetts, on December 7, 1979, aged 79. Shortly before her death, Payne had her autobiography privately printed as The Dyer's Hand. It was later reprinted as Cecilia Payne-Gaposchkin: An Autobiography and Other Recollections.[15]
Payne's younger brother, Humfry Payne (1902–1936), who married author and film critic Dilys Powell, became director of the British School of Archaeology at Athens, where he died in 1936, aged 34.[44] Payne's granddaughter, Cecilia Gaposchkin, is a professor of late medieval cultural history and French history at Dartmouth College, New Hampshire.[45][46][47]
Published academic books:
Significant research papers:
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