Antonia Caetana de Paiva Pereira Maury (March 21, 1866 – January 8, 1952) was an American astronomer who was the first to detect and calculate the orbit of a spectroscopic binary.

She was named in honor of her maternal grandmother, Antonia Caetana de Paiva Pereira Gardner Draper, the daughter of a physician at the court of John VI of Portugal and Charlotte of Spain.

[5] In 1887, Edward Charles Pickering had found the first spectroscopic binary or double star, ζ1 Ursae Majoris (Mizar A).

Herschel asked Pickering "to convey to Miss Maury my congratulations on having connected her name with one of the most notable advances in physical astronomy ever made.

In both cases the only mention of Maury was a single line, stating that "a careful study of the results has been made by Miss.

[1][5][8] In 1888,[3] Maury was assigned to observe stellar spectra of bright stars in the northern celestial hemisphere and catalog them.

[10][11] The Harvard Observatory staff used an alphabetical system of classification designed by Williamina P. Fleming and Annie Jump Cannon.

Spectra of Bright Stars Photographed With the 11-Inch Draper Telescope As Part of the Henry Draper Memorial and Discussed by Antonia C. Maury Under the Direction of Edward Charles Pickering (1897) presented the results of Maury's examination of 4,800 stellar photographs, using her own system of classification, and analyzed 681 bright northern stars in detail.

[12][1][13] Pickering and others at the observatory disagreed with Maury's system of classification and explanation of differing line widths, and refused to use it.

[5][1] Hertzsprung wrote to Pickering:[14] In my opinion the separation by Antonia Maury of the c-and ac stars is the most important advancement in stellar classification since the trials by Vogel and Secchi ... To neglect the c-properties in solar spectra, I think, is nearly the same thing as if the zoologist, who had detected the deciding differences between a whale and a fish, would continue in classifying them together.In 1922, the International Astronomical Union (IAU) modify its classification system based on the work done by Maury and Hertzsprung, a formulation known as the Hertzsprung–Russell diagram.

[17] Her work summarizing many years of research on the spectroscopic analysis of the binary star Beta Lyrae was published in 1933.

[20][21] In 1978, the Revised MK Spectral Atlas for Stars Earlier Than the Sun honored "Antonia C. Maury, Master Morphologist of Stellar Spectra" in its dedication.

[23] For three years, Maury also served as curator of the John William Draper House in Hastings-on-Hudson, New York, where her grandfather and uncle had built observatories, and where the first photos of the moon as seen through a telescope were taken.