Distinguished Women of Past and Present

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Williamina Paton Stevens Fleming


Mina Stevens Fleming, the first to discover stars called "white dwarfs", was born May 15, 1857 in Dundee, Scotland. She attended public schools in Dundee and then taught in Dundee from age fourteen until her marriage to James Fleming in 1877. The couple emigrated to Boston when she was twenty-one. A year later she was abandoned by her husband while pregnant with their child. To support herself and the baby, Mina Fleming obtained work as a maid in the home of Prof. Edward Pickering, the director of the Harvard Observatory.

Pickering was unhappy with the work performed by his male employees and declared that his maid could do a better job than they did. In fact, he hired her in 1881 to do clerical work and some mathematical calculations at the Observatory. Fleming soon proved that she was also capable of doing science. She devised a system of classifying stars according to their spectra, a distinctive pattern produced by each star when its light is passed through a prism. She used this system, which was later named after her, to catalog successfully over 10,000 stars within the next nine years. This work was published in 1890 in a book titled Draper Catalogue of Stellar Spectra.

Her duties were expanded and she was put in charge of dozens of young women hired to do mathematical computations, the work nowadays done by computers. She also edited all publications issued by the observatory. The quality of her work was so superior that in 1898 Harvard Corporation appointed her curator of astronomical photographs. This was the first such appointment given to a woman.

In 1906 she was the first American woman elected to the Royal Astronomical Society. In 1907 she published a study of 222 variable stars she had discovered. A British astronomer made the following observation: "Many astronomers are deservedly proud to have discovered one...the discovery of 222...is an achievement bordering on the marvellous." Her achievement is especially noteworthy when one takes into account that she had no formal higher education. In 1910 she published her discovery of "white dwarfs," stars that are very hot and dense and appear bluish or white in color. "White dwarfs" are believed to be stars in a final stage of their existence. Williamina Fleming died May 21, 1911 in Boston, Massachusetts.

Contributed by Danuta Bois, 1996.

1. American Women's History by Doris Weatherford, Prentice Hall General Reference, 1994
2. The Book of Women's Firsts: Breakthrough Achievements of Almost 1,000 American Women by Phyllis J. Read and Bernard L. Witlieb, Random House, 1992

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