Who Was Annie Jump Cannon?

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Annie Jump Cannon (1863-1941) was an American astronomer who manually classified over 350,000 stars at Harvard College Observatory. She created the OBAFGKM stellar classification system still used today. She was one of the Harvard Computers, a group of women who performed important astronomical work.

Annie Jump Cannon classified more stars than anyone else in history, doing the work by hand from photographic plates. Her stellar classification system, which sorts stars by temperature into seven main types, is still used today. She was one of the most productive astronomers of her era and a pioneer for women in astronomy, despite being almost completely deaf.

Who was Annie Jump Cannon?

An American astronomer born in 1863 in Dover, Delaware. She studied physics and astronomy at Wellesley College, graduating in 1884. After several years away from astronomy, she returned to the field at Radcliffe College and then joined Harvard College Observatory in 1896. She became one of the Harvard Computers, a group of women (mostly underpaid) who performed astronomical calculations and stellar classification. She lost most of her hearing to scarlet fever in her youth but became a prolific astronomer, working at Harvard for over 40 years.

What did she discover?

Or rather classify, hundreds of thousands of stars. Cannon manually classified over 350,000 stars by examining photographic plates of their spectra. She could classify three stars per minute at her peak. Her work was published in the Henry Draper Catalogue (1918-1924), a nine-volume reference that became the foundation of stellar classification. She also discovered hundreds of variable stars and five novae. The catalogue contained classifications for over 225,000 stars when first published, and later extensions brought the total to over 350,000.

What was her classification system?

The OBAFGKM sequence, organized by stellar temperature. Cannon refined an earlier system into the modern stellar classification we still use today. Stars are sorted into seven main types based on their spectra: O (hottest, blue), B, A, F, G (Sun-type), K, M (coolest, red). The mnemonic 'Oh Be A Fine Girl/Guy, Kiss Me' is the standard memory aid taught in astronomy classes. The system's foundation in temperature has held up as later astronomers understood the physics behind stellar spectra, and Cannon's classifications are still referenced today.

What's her legacy?

Significant despite the discrimination she faced. The Annie Jump Cannon Award is presented to outstanding female astronomers early in their careers. She was the first woman to receive an honorary doctorate from Oxford and the first woman officer of the American Astronomical Society. She was deaf and faced limited professional opportunities, but produced more stellar classifications than anyone before or since. The crater Cannon on the Moon and an asteroid (1120 Cannonia) are named for her. She's recognized as one of the most influential astronomers of her era.

Annie Jump Cannon was the American astronomer who manually classified over 350,000 stars and created the OBAFGKM stellar classification system still used today. Working at Harvard College Observatory for over 40 years, she became one of the most prolific astronomers in history. Despite being deaf and facing the limited opportunities available to women in her era, she achieved more than most of her contemporaries and helped open paths for women in science.

Who Was Annie Jump Cannon?