Cecilia Payne: The Astronomer Who Discovered What Stars Are Made Of

A Childhood Between England and Passion for Science

Born on May 10, 1900 in Wendover, England, Cecilia Helena Payne (1900-1979) developed an early interest in science. Her father, a historian and lawyer, encouraged her intellectual curiosity. At 19, she attended a lecture by Arthur Stanley Eddington (1882-1944) about the 1919 eclipse that confirmed the theory of general relativity. This lecture changed the course of her life.

An Academic Journey Filled with Obstacles

In 1919, she received a scholarship to study botany, physics, and chemistry at Newnham College, Cambridge. However, Cambridge did not award degrees to women before 1948. She completed her studies without an official degree.

In 1923, she emigrated to the United States where she obtained a fellowship to work at the HCO. She became the first woman to earn a PhD in astronomy (1925) with a revolutionary thesis on the composition of stars.

The Thesis That Changed Astronomy

In her thesis titled "Stellar Atmospheres," Payne demonstrated that:

• Stars are primarily composed of hydrogen (about 90%) and helium (almost 10%)
• Other elements make up only a tiny fraction (about 1-2%)
• The Sun has a similar composition to other stars

These conclusions, initially rejected by astronomers like Henry Norris Russell (1877-1957), were confirmed a few years later. Her work laid the foundation for modern astrophysics.

A Career Marked by Major Discoveries

After her PhD, Payne stayed at Harvard where she:

• Studied variable stars with Harlow Shapley (1885-1972)
• Published several fundamental books on stars and the Milky Way
• Became the first female professor at Harvard in 1956
• Led the astronomy department from 1956 to 1960

Legacy and Late Recognition

Despite her major contributions, Payne had to fight against sexist prejudices throughout her career. Her work enabled:

• Understanding of stellar evolution
• Development of stellar spectroscopy
• Modern classification of stars

She finally received the recognition she deserved with distinctions such as the Henry Norris Russell Prize in 1976.