Henrietta Swan Leavitt was an American astronomer who in the early 1900s discovered the period-luminosity relationship for Cepheid variable stars. This discovery allowed astronomers to estimate the distances to faraway galaxies and nebula and laid the foundation for the study of extragalactic astronomy.
Born in 1868 in Massachusetts Leavitt was always interested in the stars and after graduating from college she took a job at the Harvard College Observatory in 1894. She was initially hired to help astronomers measure and catalog stars on photographic plates. Leavitt soon began to notice that some stars now known as Cepheid variables changed in brightness over time.
She began to study these stars in detail and in 1912 discovered that there was a relationship between a Cepheid’s brightness and its pulsation period – the longer the period the brighter the star. Leavitt’s discovery allowed astronomers to calibrate the Cepheid period-luminosity relationship and use it to estimate the distances to galaxies and nebula.
Leavitt’s work was largely unrecognized during her lifetime but her discovery revolutionized astronomy and laid the foundation for the study of extragalactic astronomy. She died in 1921 at the age of 53 from complications of cancer.
What did Henrietta Swan Leavitt discover?
Henrietta Swan Leavitt discovered the relationship between the luminosity and period of Cepheid variable stars.
What did this discovery allow for?
This discovery allowed for the measurement of the distances to remote galaxies.
How did Leavitt’s discovery come about?
Leavitt’s discovery came about through her work at Harvard College Observatory where she was cataloguing stars.
How did Leavitt measure the luminosity of stars?
Leavitt measured the luminosity of stars by comparing their apparent magnitude (how bright they appear from Earth) to their absolute magnitude (how bright they actually are).
What is the period-luminosity relation?
The period-luminosity relation is the relationship between the luminosity and period of Cepheid variable stars.
What is the significance of the period-luminosity relation?
The period-luminosity relation allows for the calculation of the distances to remote galaxies.
How do Cepheid variable stars allow for the measurement of remote galaxy distances?
Cepheid variable stars allow for the measurement of remote galaxy distances because their luminosity can be determined from their period.
What is the Hertzsprung-Russell diagram?
The Hertzsprung-Russell diagram is a graph that plots the luminosity of stars against their surface temperature.
How did Leavitt use the Hertzsprung-Russell diagram?
Leavitt used the Hertzsprung-Russell diagram to identify Cepheid variable stars.
What are Cepheid variable stars?
Cepheid variable stars are stars that pulsate meaning their brightness varies over time.
Why are Cepheid variable stars important?
Cepheid variable stars are important because their luminosity can be determined from their period.
How can the luminosity of Cepheid variable stars be determined from their period?
The luminosity of Cepheid variable stars can be determined from their period because of the period-luminosity relation.
What is the period-luminosity relation?
The period-luminosity relation is the relationship between the luminosity and period of Cepheid variable stars.
How can the period-luminosity relation be used to measure the distances to remote galaxies?
The period-luminosity relation can be used to measure the distances to remote galaxies because the luminosity of Cepheid variable stars can be determined from their period.
How did Henrietta Swan Leavitt’s discovery change astronomy?
Henrietta Swan Leavitt’s discovery changed astronomy because it allowed for the measurement of the distances to remote galaxies.
