Born: 26 October 1902, United States
Died: 24 November 1980
Country most active: United States
Also known as: NA
The following bio was written by Emma Rosen, author of On This Day She Made History: 366 Days With Women Who Shaped the World and This Day In Human Ingenuity & Discovery: 366 Days of Scientific Milestones with Women in the Spotlight, and has been republished with permission.
Henrietta Hill Swope was an American astronomer who studied stars that change in brightness, especially Cepheid stars. By figuring out how long these stars brighten and dim, she could work out how far away they were. This helped her measure the size of the Milky Way and the distances to other galaxies.
Henrietta Hill Swope began her career working with Dr. Shapley at Harvard in 1926, joining a group of women identifying variable stars in the Milky Way. She formed close relationships with Cecilia Payne-Gaposchkin and Adelaide Ames. She financed her work through Harvard and family support while becoming an expert at estimating star magnitudes from photographic plates.
In 1942, she moved to MIT’s staff radiation laboratory, contributing to LORAN navigation tables. From 1947 to 1952, she taught astronomy at Barnard College and Connecticut College for Women and conducted research using Harvard’s old plates.
In 1952, she was invited by Walter Baade of the Carnegie Institution to work on variable stars detected in other galaxies using the new 200-inch Hale Telescope at Palomar Observatory. She remained at the Carnegie Institution, working independently after Baade’s passing, and officially retired in 1968.
In 1964, a joint paper with Baade reported her findings on Cepheid stars in the Andromeda Galaxy, revealing a new distance estimate for M31. In 1963, she refined this estimate for a specific region in Andromeda.