Cecilia Payne-Gaposchkin

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Cecilia Payne-Gaposchkin
Cecilia Payne-Gaposchkin
Cecilia Payne-Gaposchkin
Born May 10, 1900
Wendover
Died December 7, 1979
Nationality English-American
Fields astronomy
Institutions Cambridge University
Known for Sun is mainly composed of hydrogen
Signature
Cecilia Payne-Gaposchkin's signature

Cecilia Payne-Gaposchkin (May 10, 1900 – December 7, 1979) was an English-American astronomer who in 1925 was first to show that the Sun is mainly composed of hydrogen, contradicting accepted wisdom at the time.

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[edit] Early life

Cecilia Helena Payne was one of three children born in Wendover, England to Elena (Pertz) and Edward John Payne, a London barrister, historian and accomplished musician. Her father died when she was four years old, forcing her mother to raise the family on her own. She attended St Paul's Girls' School and then won a scholarship to read botany, physics and chemistry at Newnham College, Cambridge University in 1919. Here, her interest in astronomy was sparked by Eddington's lecture on his eclipse expedition to Brazil to photograph the stars near the eclipsed Sun as a test of Einstein's general theory of relativity.

She completed her studies but was not awarded a degree as Cambridge did not grant degrees to women at that time. After meeting Harlow Shapley, the Director of the Harvard College Observatory, who had just begun began a graduate program in astronomy, she left England for the United States in 1923. This was made possible by a fellowship to encourage women to study at the Observatory. The first student was Adelaide Ames (1922); the second student was Payne.

[edit] Doctorate

Shapley persuaded her to write a doctoral dissertation, and so in 1925, she became the first person to earn a Ph.D. in astronomy from Harvard for her thesis: "Stellar Atmospheres, A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars". Astronomer Otto Struve characterized it as "undoubtedly the most brilliant Ph.D. thesis ever written in astronomy". By applying the ionization theory developed by Indian physicist Megh Nad Saha she was able to accurately relate the spectral classes of stars to their actual temperatures. She showed that the great variation in stellar absorption lines was due to differing amounts of ionization that occurred at different temperatures, and not due to the different abundances of elements. She correctly suggested that silicon, carbon, and other common metals seen in the sun were found in about the same relative amounts as on earth but the helium and particularly hydrogen were vastly more abundant (by about a factor of one million in the case of hydrogen). The thesis thus established that hydrogen was the overwhelming constituent of the stars. When her thesis was reviewed, she was dissuaded by Henry Norris Russell from concluding that the composition of the sun is different from the earth, which was the accepted wisdom at the time. However Russell changed his mind four years later when other evidence emerged.

[edit] Personal life

She became an American citizen in 1931. On a tour through Europe in 1933, she met Russian-born Sergei I. Gaposchkin in Germany. She helped him get a visa to the United States and they married in March 1934, and eventually had three children, Edward, Katherine and Peter. Payne-Gaposchkin remained scientifically active throughout her life, spending her entire academic career at Harvard. At one point she considered leaving Harvard because of her low status and poor salary as she held no official position there. She served as a technical assistant to Shapley from 1927 to 1938. Shapley, however, made efforts to improve her position and in 1938 was she given the title of "astronomer". In 1956 she became the first female tenured professor at Harvard, and by her appointment to the Chair of the Department of Astronomy, she also became the first woman to head a department at Harvard.

[edit] Later research

After her doctorate Payne then studied stars of high luminosity in order to understand the structure of the Milky Way. Later with her husband, she surveyed all the stars brighter than the tenth magnitude. She then studied variable stars, making, with her assistants over 1,250,000 observations. This was later extended to the Magellanic Clouds, adding a further 2,000,000 observations of variable stars. This data was used to determine the paths of stellar evolution.

[edit] Appraisal of her career

According to G. Kass-Simon and Patricia Farnes, her career marked a sort of turning point at Harvard College Observatory. Under the direction of Harlow Shapley, the observatory had already offered more opportunities in astronomy to women than other institutions, and notable achievements had been made earlier in the century by Williamina Fleming, Antonia Maury, Annie Jump Cannon, and Henrietta Leavitt. However with Payne-Gaposchkin's Ph.D., women entered the 'mainstream'. The trail she blazed into the largely male-dominated scientific community was an inspiration to many.

[edit] Books

She published several books including:

  • "Stars of High Luminosity" (1930),
  • "Variable Stars" (1938),
  • "Variable Stars and Galactic Structure" (1954),
  • "Introduction to Astronomy" (1956),
  • "The Galactic Novae" (1957),
  • "The Dyer’s Hand: An Autobiography" (1979).

[edit] Honors

Awards

[edit] Quotation

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 to 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.
—Cecilia Payne-Gaposchkin (accepting the Henry Norris Russell Prize from the American Astronomical Society)

[edit] Bibliography

[edit] Further reading

  • Rubin, Vera (2006), "Cecilia Payne-Gaposchkin" in OUT OF THE SHADOWS: Contributions of 20th Century Women to Physics, Nina Byers and Gary Williams, ed., Cambridge University Press (ISBN-13: 9780521821971 | ISBN-10: 0521821975).

[edit] External links