Helen Sawyer Hogg

Born on 1 August 1905 in Lowell, Massachusetts, Helen Sawyer Hogg was an astronomer who specialized in galaxy clusters and variable stars. She earned her bachelor’s degree in astronomy from Mount Holyoke College in 1926, and her master’s and PhD degrees from Radcliffe College in 1928 and 1931, respectively. It was at Radcliffe that she began her life’s work, researching variable stars in globular clusters. In 1931 she moved to Canada, where she worked first at the Dominion Astrophysical Observatory in Victoria, British Columbia, before settling permanently in 1935 at the University of Toronto’s David Dunlap Observatory. There she continued her research and joined the teaching staff of the astronomy department. In 1939 she produced her venerable Catalogue of Variable Stars in Globular Clusters, which she updated in 1955 and 1973. Hogg’s research on variable stars, and her discovery that they contain varying amounts of heavy metals, helped shape astronomers’ understanding of the age and evolution of our galaxy. In addition to her academic work, Hogg performed many science outreach efforts. From 1951 to 1981, she wrote a weekly newspaper column called “With the stars” for the Toronto Star. In 1970 Hogg hosted an astronomy TV series, and in 1971 she helped found the Astronomical Society of Canada and became its first president. Even after retiring in 1976, she continued her astronomy outreach efforts with the publication of her popular guide The Stars Belong to Everyone. Over her career, Hogg studied some 2000 variable stars, published more than 200 papers, and received a number of awards and honors, including the Annie Jump Cannon Award of the American Astronomical Society in 1949 and appointment as Companion of the Order of Canada in 1976. She died in 1993 at age 87. (Photo credit: AIP Emilio Segrè Visual Archives, John Irwin Slide Collection)

Date in History: 1 August 1905