Cecilia Payne-Gaposchkin

• Born: May 10, 1900
• Birthplace: Wendover, England
• Died: December 6, 1979
• Place of death: Cambridge, Massachusetts

English American astronomer

Astronomer Cecilia Payne-Gaposchkin was the first person to receive a PhD in astronomy from Harvard University and the first female professor there. While studying stellar atmospheres and the composition of stars, she suggested that their most abundant element is hydrogen.

Born: May 10, 1900; Wendover, England

Died: December 7, 1979; Cambridge, Massachusetts

Primary field: Astronomy

Specialties: Observational astronomy; astrophysics

Early Life

Cecilia Helena Payne was born in Wendover, Buckinghamshire, England, on May 10, 1900, the oldest of the three children of Edward Payne and Emma Pertz. Her father, a scholar, musician, and lawyer, died when she was four, and she and her two siblings were raised by their mother.

For six years, Payne-Gaposchkin attended a small private elementary school near her home. When she was about eight years old, she saw her first meteorite and immediately became interested in astronomy. In 1910, she witnessed both the great daylight comet (C/1910 A1) and Halley’s comet, which further fueled her interest.

In 1912, Payne-Gaposchkin’s family moved to London, where she attended a school run by the Church of England. Her education there concentrated on classical languages; preferring science, Payne-Gaposchkin studied botany and math on her own. She insisted on being examined in botany and scored top marks on the exam. She also found a tutor to help her learn German, a language vital for scientists at the time.

In 1917, Payne-Gaposchkin transferred to St. Paul’s Girls’ School, where she was able to study science. In 1919, thanks to a scholarship, she entered Newnham College at Cambridge University, where she majored in biology. After attending a lecture by English astrophysicist Arthur Eddington, Payne-Gaposchkin’s interest shifted to the physical sciences. She was the only woman to attend astronomy lectures and worked on her own at the college observatory, where she met future English astronomer Edward A. Milne. After graduating in 1923, Payne-Gaposchkin won a National Research Council fellowship, which she used to pursue graduate work at Radcliffe College, a women’s college affiliated with Harvard University.

Life’s Work

Payne-Gaposchkin was assigned to the Harvard College Observatory under its new director, Harlow Shapley, who became her thesis advisor and mentor and persuaded her to work toward her PhD. In the absence of an astronomy program, Payne-Gaposchkin completed her research at the observatory.

At the time, the sun was believed to be composed mostly of iron. Spectroscopic readings, or measurements of the composition of matter in a celestial body, can overlap, and the results may depend on how they are broken apart; in the course of her research, Payne-Gaposchkin interpreted the spectroscopic readings in a new way and reached the conclusion that the sun is primarily composed of hydrogen, with helium being the second most abundant element. Numerous astronomers, including Eddington, insisted that she was wrong. Only Milne supported her thesis. Payne-Gaposchkin fought for her conclusion, but in order to have her thesis accepted, she was forced to include a statement that the presence of hydrogen in the sun was highly unlikely.

Payne-Gaposchkin’s doctoral thesis, Stellar Atmospheres: A Contribution to the Observational Study of Matter at High Temperatures, was published in 1925. In it, she established a stellar temperature scale and affirmed that in spite of seeming variations, all stars have essentially the same composition. Payne-Gaposchkin was granted a PhD in astronomy at the age of twenty-five, making her the first person to receive a doctorate in the subject from either Harvard University or Radcliffe College. The following year, she became the youngest astronomer to appear in the biographical reference American Men of Science.

By 1929, the work of independent scientists, particularly Russian astronomer Otto Struve, had proved Payne-Gaposchkin’s theory of the sun’s composition correct. Struve offered to credit her for the discovery, but she felt that she did not deserve recognition because she had capitulated even when she knew she was right. However, she has since been recognized as the first to discover the composition of the sun.

Payne-Gaposchkin became a United States citizen in 1931. In 1933, she traveled to Russia and Germany. At an astronomy conference at the University of Göttingen, Germany, she met astronomer Sergei I. Gaposchkin, a Russian refugee. He had come to the meeting specifically to meet Payne-Gaposchkin but was unable to stay in Germany because of the recent Nazi takeover. When Payne-Gaposchkin returned to Harvard, she used her influence to bring Gaposchkin to the United States, where he was given a position at Harvard. The couple married in 1934 and went on to have three children. Payne-Gaposchkin’s daughter, Katherine, would later become an astronomer and collaborate with her mother on several papers.

Payne-Gaposchkin also collaborated with her husband on many astronomical investigations and publications. Over the course of their study of variable stars, which are stars that change in magnitude (brightness) over time, the two examined 1,500 specimens and reported their preliminary findings in three monographs in 1935. In a 1936 report to the National Academy of Sciences, Payne-Gaposchkin suggested that supernovas differ from normal novas only in size, and in 1938, she and her husband published Variable Stars to provide evidence to support their preliminary conclusions. That year, Payne-Gaposchkin was named Phillips Astronomer at Harvard College Observatory and became a lecturer in astronomy.

During the 1940s, Payne-Gaposchkin continued her research projects with her husband, independently, and with other staff members at the Harvard Observatory. In 1946, she reported in the Astrophysical Journal on the variable binary star RT Andromedae. Two years later, she and her husband presented their final report on variable stars to the American Philosophical Society. In 1949, at an energy conference at Wellesley College in Massachusetts, Payne-Gaposchkin explained how the sun consumes its own substance and then renews its energy from the atomic cores, or nuclei, with hydrogen as the fuel and helium the “ash.” She compared this process to that which occurs in an atomic bomb.

Throughout the 1950s, Payne-Gaposchkin published several works, including Stars in the Making (1952); Variable Stars and Galactic Structure (1954), a synopsis of a presentation at the University of London; Introduction to Astronomy (1954, 1956); and The Galactic Novae (1957). She also wrote numerous articles on spiral galaxies and other subjects. In 1956, she was made a full professor of astronomy at Harvard and was promoted to chair of the astronomy department, the first woman appointed to both positions. She battled for increased pay, but although her salary was raised, she still made less than beginning male lecturers.

In the late 1960s, Payne-Gaposchkin collaborated with her daughter on a revised second edition of Introduction to Astronomy, which was published in 1970. Nine years later, she collected and collated family correspondence dating back to 1830. She completed the collection, which she called The Garnet Letters, in 1979.

Payne-Gaposchkin received honorary degrees from Wilson College, Smith College, the Western College for Women, Colby College, the Women’s Medical College of Philadelphia, and Cambridge University. She was the first to receive the Annie Jump Cannon Award from the American Astronomical Society in 1934. She was also granted the Radcliffe Award of Merit for outstanding scientific achievements in 1952 and the American Astronomical Society’s Henry Norris Russell Prize in 1976. She was a member of the Royal Astronomical Society, the American Academy of Arts and Sciences, the American Astronomical Society, and the American Philosophical Society.

Payne-Gaposchkin died of lung cancer on December 7, 1979.

Impact

The asteroid 2039 Payne-Gaposchkin, discovered in 1974, was named in Payne-Gaposchkin’s honor in 1977. As the first astronomer to graduate with a doctoral degree in astronomy from Harvard University and the first female professor and department chair at Harvard, Payne-Gaposchkin helped establish both the field of astronomy at a postgraduate level and a place for women in that field. In her determination to study what she loved, she was able to contribute prolifically to astronomy, and she earned respect in a scientific community overwhelmingly dominated by men.

Payne-Gaposchkin determined the sun’s composition and the composition of stars in general, and her collection of stellar data resulted in numerous publications for astronomers and students of astronomy. This, in turn, impacted scientists’ understanding of the nature of variable stars, stellar atmospheric temperature, and the elemental composition of stars. By combining stellar astronomy with atomic physics, Payne-Gaposchkin’s research helped develop the study of stellar composition within the field of astrophysics. Understanding a star’s composition can help scientists determine that star’s evolution, thus contributing to our basic understanding of the universe.

Bibliography

Kaler, James B. Stars and Their Spectra: An Introduction to the Spectral Sequence. 2nd ed. New York: Cambridge UP, 2011. Print. An overview of stellar spectroscopy. Covers the fundamental properties of various types of stars and their spectra.

Payne-Gaposchkin, Cecilia. Cecilia Payne-Gaposchkin: An Autobiography and Other Recollections. 1984. New York: Cambridge UP, 1996. Print. Payne-Gaposchkin’s life and work. Includes her bibliography and introductory material by her daughter and other female astronomers.

Percy, John R. Understanding Variable Stars. New York: Cambridge UP, 2004. Print. Overview of variable stars and the information their variations in magnitude provide about the stars’ properties, composition, and evolution.