Cecilia Payne-Gaposchkin | |
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| Born | Cecilia Helena Payne (1900-05-10)May 10, 1900 Wendover, Buckinghamshire, England |
| Died | December 7, 1979(1979-12-07) (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 theSun, more than 3,000,000 observations of variable stars |
| Spouse | |
| Children | 3 |
| Relatives |
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| 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 |
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Cecilia Payne-Gaposchkin (bornCecilia Helena Payne;(1900-05-10)May 10, 1900 –(1979-12-07)December 7, 1979) was a British-born Americanastronomer andastrophysicist. In her 1925doctoral thesis she determined thatstars were composed primarily ofhydrogen andhelium.[1]
Her groundbreaking conclusion was initially rejected by leading astrophysicists, includingHenry Norris Russell,[2] because it contradicted the science of the time, which held that no significant elemental differences distinguished theSun andEarth. Independent observations eventually proved that she was correct.[1][2][3][4]
Despite completing her studies, Payne was unable to receive a degree from theUniversity of Cambridge as a woman.[5] In America, she was unable to receive her PhD fromHarvard University, as they did not grant doctoral degrees to women at the time.[6] She instead received her doctoral degree fromRadcliffe College[6] – a female liberal arts college that started as a program within Harvard.
Overcoming barriers for women in science, her work on the cosmic makeup of the universe and the nature ofvariable stars was foundational to modern astrophysics. She was elected to theRoyal Astronomical Society while she was a student at Cambridge[7] and later became the first recipient of the American Astronomical Society’s prestigiousAnnie Jump Cannon Award in Astronomy.[8] Her success also opened the door for countless female astronomers, including her Harvard colleague,Helen Sawyer Hogg,[9] and in 1956, she was appointed Harvard’s first female Professor and female Department Chair.[10]
Cecilia Helena Payne, born inWendover in Buckinghamshire, England,[11] was one of three children to Emma Leonora Helena (née Pertz) andEdward John Payne, a Londonbarrister, historian and musician who had been anOxford fellow.[12] Her mother came from aPrussian family and had two distinguished uncles, historianGeorg Heinrich Pertz and theSwedenborgian writerJames John Garth Wilkinson.[13] 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.[14] When Payne was twelve, her family moved to London to support her brotherHumfry'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 toSt 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 atNewnham College, Cambridge University, where she studied physics and chemistry.[12]
Her interest in astronomy began after she attended a lecture byArthur Eddington, detailing his1919 expedition to the island ofPríncipe in theGulf of Guinea off the west coast of Africa to observe and photograph the stars near asolar eclipse as a test ofAlbert Einstein'sgeneral theory of relativity.[15] 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."[16]: 117 Although she completed her studies, she did not receive an official degree, because Cambridge did not grant degrees to women until 1948.[17]
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 toHarlow Shapley, the Director of theHarvard College Observatory, after a lecture inLondon at theBritish Astronomical Association.[5][15][18] In 1923, Payne moved to the United States to study atHarvard College, enabled by a fellowship established to encourage women to study at theHarvard 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.[19]
Shapley persuaded Payne to write a doctoral dissertation, and so in 1925 she became the first person to earn a PhD in astronomy fromRadcliffe College ofHarvard University.[15][20] Her thesis title wasStellar Atmospheres; A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars.[1][21]
While analyzing glass plates at the Harvard College Observatory,[5] Payne made a groundbreaking discovery by accurately relating thespectral classes ofstars to their actual temperatures using Indian physicistMeghnad Saha'sionization theory. She demonstrated that the great variation in stellarabsorption lines was due to differing amounts ofionization at different temperatures, not to varying amounts of elements. Payne found thatsilicon,carbon, and several commonmetals 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 thathelium, and particularlyhydrogen, 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.[22][23]
However, when Payne's dissertation was reviewed,Henry Norris Russell, a pre-eminent astronomer of the day who adhered to the theories of American physicistHenry 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.[24] 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.[25]
Consequently, Russell described her results as "spurious".[21]: 186 [23] 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 [...]".[26] Nevertheless, Russell was generally credited for the conclusions she had reached four years prior.[26][27]
Nearly 40 years after Payne's thesis was published, astronomerOtto Struve described her work as "the most brilliant PhD thesis ever written in astronomy".[2][28] Today's accepted ratios for hydrogen and helium in theMilky Way Galaxy are ~74% hydrogen and ~24% helium, confirming the results of Payne-Gaposchkin's calculations from 1925.[29]
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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 theMilky Way. Later she surveyed all stars brighter than the tenthmagnitude. She then studiedvariable stars, making over 1,250,000 observations with her assistants. This work later was extended to theMagellanic Clouds, adding a further 2,000,000 observations of variable stars.
These data were used to determine the paths ofstellar evolution. She published her conclusions in her second book,The Stars of High Luminosity (1930).[22] On a tour throughEurope in 1933, Payne met Russian-bornastrophysicistSergei Illarionovich Gaposchkin [ru] inGermany. 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, includingThe Stars of High Luminosity (1930),Variable Stars (1938) andVariable Stars and Galactic Structure (1954).Harlow Shapley (the Director of theHarvard 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, anendowed 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".[16]: 225 [30][31] She was elected a Fellow of theAmerican Academy of Arts and Sciences in 1943.[32] Her courses were not recorded in the Harvard University catalogue until 1945.[1]
WhenDonald Menzel became Director of theHarvard 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 atHarvard's Faculty of Arts and Sciences.[15] She was appointed the Phillips Professor of Astronomy in 1958.[31] 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 includedJoseph Ashbrook,Frank Drake,Harlan Smith andPaul W. Hodge, all of whom made important contributions to astronomy.[33] She also supervisedHelen Sawyer Hogg,Frank Kameny[34] andOwen Gingerich.[35]
Payne-Gaposchkin retired from active teaching in 1966 and was subsequently appointedProfessor Emerita of Harvard.[3] She continued her research as a member of staff at theSmithsonian Astrophysical Observatory, as well as editing the journals and books published by Harvard Observatory for ten years.[36] She edited and published the lectures ofWalter Baade asEvolution of Stars and Galaxies (1963).[37]
Payne-Gaposchkin's career marked a turning point at Harvard College Observatory. Under the direction ofHarlow Shapley and Dr. E. J. Sheridan (whom Payne-Gaposchkin described as a mentor[16]), 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 byWilliamina Fleming,Antonia Maury,Annie Jump Cannon, andHenrietta Swan Leavitt. However, with Payne's PhD, women entered the mainstream.[38]
The trail she blazed into the largely male-dominated scientific community was an inspiration to many. For example, she became a role model for astrophysicistJoan Feynman. Feynman's mother and grandmother had dissuaded her from pursuing science, since they believed women were not physically capable of understanding scientific concepts.[39][40][41] 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.[39]
While accepting theHenry Norris Russell Prize from theAmerican 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."[42]
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In herautobiography, Payne said that while in school she created an experiment on theefficacy 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.[16]: 97 Later on, she became anagnostic.[43]
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 astrophysicistSergei Illarionovich Gaposchkin [ru] in Germany. She helped him get a visa to the United States, and they married in March 1934, settling in the historic town ofLexington, 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 FirstUnitarian Church in Lexington, where Cecilia taught Sunday school. She was also active with theQuakers.[44]
During the war years, work at the observatory was virtually stopped, but Payne and her husband continued, often taking their children with them to work.They lived in Lexington, while on a small farm they had nearTownsend, a neighbour helped them raise pigs and poultry and deliver meat and eggs to local markets.[45]
She died at her home in Cambridge, Massachusetts, on December 7, 1979, aged 79. Shortly before her death, Payne had her autobiography privately printed asThe Dyer's Hand. It was later reprinted asCecilia Payne-Gaposchkin: An Autobiography and Other Recollections.[16]
Payne's younger brother,Humfry Payne (1902–1936), who married author and film criticDilys Powell, became director of theBritish School of Archaeology at Athens, where he died in 1936, aged 34.[46] Payne's granddaughter, Cecilia Gaposchkin, is a professor of late medieval cultural history and French history atDartmouth College, New Hampshire.[47][48][49]
Published academic books:
Significant research papers:
Payne, Humfrey Gilbert Garth... figlio unico dello storico Edward John Payne e di sua moglie Emma Leonora Helena Pertz, nipote di Georg Heinrich Pertz, il curatore dei "Monumenta Germaniae Historica", e di James John Garth Wilkinson, il discepolo di Swedenborg.
Since she actually got better marks in the prayerless group she became, and remained, a devout agnostic.
A September 1956 article inThe Christian Register published by the American Unitarian Association, announced her appointment and described her as a member of the denomination's First Parish and Church in Lexington, Massachusetts.
