Cecilia
Helena Payne-Gaposchkin(1900-1979) was a British-born astronomer who became an
authority on variable stars and the structure of the Milky Way Galaxy. She was
one of the first women to advance to the rank of professor at Harvard
University and the first woman to head a department there.
Cecilia
Helena Payne was born May 10, 1900, in Wendover, England. She entered Cambridge
University in 1919. As a woman in the field of astronomy, Payne met with many
obstacles. A prominent professor, Ernest Rutherford, whose work helped reveal
the structure of the atom, made fun of Payne as the only woman in his lectures,
making the male students laugh. Although she felt intimidated, her love of astronomy
ensured her success. She became a friend with young British astronomer Arthur
Stanley Eddington, who took her on as a tutorial student. Eddington went on to
pioneer in the investigation of the internal structure of stars.
Payne
completed her studies at Cambridge in 1923, earning a B.A. degree in 1923.
Since at that time a woman could only earn “the Title of a Degree,” Payne
sailed to the United States in 1923 to
seek greater opportunities. That year, she began studying at Radcliffe College,
a private liberal arts college for women in Cambridge, Massachusetts, with
close ties to Harvard University.
Not long
before Payne came to America, the director of the Harvard College Observatory,
Harlow Shapley, had started an astronomy program to encourage women to study at
the Observatory. She was the second student to study at the observatory. Payne
worked extensively at the Observatory, and Shapley became her thesis adviser.
In two years, she earned a Ph.D. degree in astronomy from Radcliffe, the first doctorate
awarded for research at the Harvard Observatory. Harvard had not yet
established a doctoral program in the field. She also became the first woman to
receive a doctorate in astronomy from Radeliffe.
Her work
dealt with atmospheres of stars. She submitted her Ph.D. thesis—which became
the book Stellar Atmospheres —-to Radcliffe College in 1925. Ukrainian-born
American astrophysicist Otto Struve called Payne's dissertation “undoubtedly
the most brilliant Ph.D. thesis ever written in astronomy.” Struve, who
contributed much to the study of stars, was known chiefly for his
investigations of the spectra of stars.
From 1927 to
1938, she worked as Shapley's technical assistant at the Harvard Observatory.
Shapley often kept Payne from using new electronic equipment, and he was
responsible for keeping her name out of the Harvard or Radcliffe catalogs. She
learned years later that he paid her salary out of “equipment expenses.” In
1934, the American astronomer Henry Norris Russell referred to Payne when he wrote
that the best candidate in America to be his successor at Princeton University
“alas, is a woman!” Russell was highly influential in the growth of theoretical
astrophysics in the United States and was director of the observatory at
Princeton University from 1912 to 1947. Neither Harvard nor Princeton would
have considered a woman faculty member.
Also in
1934, Payne married Russian-born Harvard astronomer and astrophysicist Sergei
Gaposchkin. They worked together on many variable star projects.
Payne-Gaposchkin's
work at Harvard College Observatory remained unofficial and unacknowledged.
None of the courses she taught at Harvard were listed in the catalog until
1945. In addition, she saw how women did the grunt work in her field. In the
back rooms at the observatory, women laboured over the computations needed to
measure star locations and catalog volumes of other scientists' results. Some
of them had begun with high science talent, but had been discouraged in their
efforts. They could lose their jobs if they married or if they complained about
their low salaries.
Finally, in
1956, after a 31-year wait, Payne-Gaposchkin received the title of tenured
professor of astronomy at Harvard, a position she held until 1966. She was the
first woman to become a fully tenured professor at Harvard. At the same time,
she became the first woman department chair, heading Harvard's Department of
Astronomy from 1956 to 1960. Her own struggles as a woman in a field dominated
by men helped Payne-Gaposchkin become a strong supporter of young women
students.
Payne-Gaposchkin's
accomplishments in astronomy were numerous. She discovered the chemical
composition of stars. In particular, she discovered that hydrogen and helium
are the most abundant elements in stars and. therefore, in the universe. She
also determined stellar temperatures. She learned these things from detailed
study and analysis of the spectra of high luminosity stars. This involved analyzing light from stars in
distant galaxies by passing it through a prism, which broke it up into a
rainbow like band of colours called a spectrum. At one end of the spectrum of
visible light is red, the colour with the longest wavelength (distance between
successive wave crests). At the other end is violet, which has the shortest wavelength.
The spectrum of light sent out by any star has bright and dark lines that
indicate the composition of the star's outer layers and atmosphere. The
astronomers then compared the spectra of the light from the stars in the
distant galaxies with spectra of similar stars in our home galaxy, the Milky
Way.
The
observations and analyses of variable stars made by Payne-Gaposchkin and
Gaposchkin laid the foundation for all following work on variable stars and
their use for clues to the structure of stars. Variable stars are stars that
change their brightness. There are four main types: (1) pulsating variables,
(2) exploding stars (also called cataclysmic variables), (3) eclipsing
binaries, and (4) rotating stars.
Pulsating
variables change in brightness as they expand and contract. They pulsate every
few days to every 100 days. One type of pulsating variable is the Cepheid.
Astronomers also call these stars Cepheid variables because they discovered the
first one in the constellation Cepheus. Payne-Gaposchkin and other astronomers
could tell the distance to Cepheid variables by comparing the apparent
brightness of the stars with their luminosities. The discovery that other
galaxies are distant systems that are not part of the Milky Way was made by
observing cepheids.
Exploding
stars burst unexpectedly with such tremendous energy that they hurl huge
amounts of gas and dust into space. One type of exploding star Payne-Gaposchkin
studied is called nova, plural novae. These stars become thousands of times
brighter than normal. This brightness may last for a few days or even years,
and then the star returns to its dim appearance. Some novae explode again and
again. Another type of exploding star, called a supernova, is thousands of
times as bright as an ordinary nova.
Eclipsing
binaries are double stars, consisting of a pair of stars that move around each
other. The stars move in such a way that one periodically blocks the other's
light. This blocking reduces the total brightness of the two stars as seen from
the earth. Eclipsing binaries are only one kind of double star.
From 1966 to
1979, Payne-Gaposchkin remained an emeritus professor of Harvard, and from 1967
to 1979 she was a staff member of the Smithsonian Astrophysical Observatory.
She wrote many academic books and textbooks, as well as the popular Stars in
the Making (1952) and Stars and Clusters (1979). For 20 years, she edited the
publications of the Harvard Observatory, including the journals Bulletin,
Circular, and Annals, as well as books that appeared under the title of Harvard
Monographs.
Several
colleges awarded Payne-Gaposchkin honorary degrees. The Royal Astronomical
Society elected her a member while she was still a student at Cambridge. She
also became a member of the American Astronomical Society, American
Philosophical Society, and American Academy of Arts and Sciences. She won a
National Research Council Fellowship; Graduate Medal of the Radcliffe Alumnae
Association; Annie Jump Cannon Award of the American Astronomical Society;
Henry Norris Russell Prize, American Astronomical Society; Award of Merit,
Radcliffe College; and the Rittenhouse Medal, Franklin Institute.
Cecilia
Payne-Gaposchkin died on Dec. 7, 1979.
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