Antonia Maury

Antonia Maury's  Vassar College senior year "photograph card."
Credit: Vassar College

Antonia Caetana de Paiva Pereira Maury was born in Cold Spring, New York in March 1866 and was named after her Portuguese maternal grandmother. Maury was descended from numerous distinguished scientists and teachers, so she was exposed to scientific inquiry early in life. Maury attended Vassar College where she took classes in astronomy, English composition, philosophy, and history. Maury was also one of Maria Mitchell's students and distinguished herself through her lecture presentation on comets. Soon after graduating in 1887 with honors in astronomy, physics, and philosophy, Maury began work with Edward Pickering, the director of the Harvard Observatory at the time. She became one of the Harvard "computers" who would go on to make incredible scientific discoveries.

While at the Harvard Observatory, Maury began to study stellar spectra. [When passed through a prism, the star's light appears as separate bands of colors interspersed with darker lines. This stellar spectra provides information about a star's chemical composition, temperature, and luminosity]. Maury's uncle, Henry Draper, had been analyzing the spectra of over 100 stars when he died in 1882. A few years later, Maury became the "computer" with the task of computing and cataloging the spectra of stars in the northern hemisphere. This entailed analyzing thousands of spectral photographs for minute differences which undoubtedly required immense patience.

Fellow "computers," Williamina Fleming and Annie Jump Cannon, had devised a system for classifying the stellar spectra. Maury, however, developed her own scheme based on temperature, with divisions to describe the variation in the width and strength of the spectral lines. Maury's work on this new classification scheme was not appreciated by Pickering, who felt that her work was putting him behind schedule. Frustrated by not being able to conduct her own original work, Maury left Harvard in 1891.

An artist's impression of a spectroscopic binary.

In 1887, Pickering had discovered a spectroscopic binary, Zeta Ursae Majoris, and Maury had been given the task of determining its orbit. [Note: a spectroscopic binary is composed of two stars orbiting around a common center of mass]. In 1889, Maury had independently discovered another spectroscopic binary, Beta Aurigae, and determined its orbital period. She was the first person to calculate the orbits and periods of these two spectroscopic binaries. However, when Pickering announced the achievement in 1889, he only briefly mentioned Maury's name. So after Maury left Harvard, and Pickering had asked her to return or pass on her work, she had responded: "I do not think it is fair that I should pass the work into other hands until it can stand as work done by me. I worked out the theory at the cost of much thought and elaborate comparison and I think that I should have full credit for my theory of the relations of the star spectra." Maury did return to Harvard in 1893 and 1895 to complete a catalog of stellar classifications using her own scheme.

Although Maury's stellar classification scheme was never officially adopted by the Harvard Observatory, its value was recognized by Danish astronomer Ejnar Hertzsprung. Hertzsprung realized that there was a difference between very bright red stars (giants) and very faint ones (dwarves) which he only noticed because of Maury's stellar classification. By 1913, Hertzsprung and Henry Norris Russell independently created the Hertzsprung-Russell diagram, an important tool in describing stellar evolution. Vindication of Maury's classification scheme officially came in 1922 when the International Astronomical Union agreed to incorporate Maury's work into its classification scheme.