Welcome to CWP at UCLA 

86 Eminent Physicists

Search the Archive

Fascinating Documents

AnnotatedPhoto Gallery

In Her Own Words

Some Physics History

500+ Books and Articles

Project Staff

Field Editors

Project Support

Photo Credits


Photo of Henrietta Swan Leavitt

Henrietta Swan Leavitt

Additional Information

Some Important Contributions

Discovered the relation between the period and luminosity of classical Cepheid variable stars. This period-luminosity (P-L) relation made possible measurement of the distances of stars from the earth and the determinationof intergalactic distances by determining the distances from the earth of stars in galaxies outside our own. This relation remains of great importance in the determination of astronomical distances.

Observations that determined absolute photographic magnitudes (brightness) of a sequence of 47 star near the North Pole that could then be used as a standard of comparison to measure the absolute magnitudes (brightness) of other stars.

Discovered 1,777 variable stars in the Magellanic Clouds.

Some Important Publications

"Periods of 25 Variable Stars in the Small Magellanic Cloud," Harvard College Observatory Circular 173 (1912).

"Standard Photographic Magnitudes," Science 30:726 (1909).

"1777 Variables in the Magellanic Clouds", Annals of Harvard College Observatory 15: 87 (1908)


Honorary Member, American Association of Variable Star Observers


1895-1900 Volunteer Research Assistant, Harvard College Observatory

1902-1921 Staff Member, Harvard College Observatory
Head, Department of Photographic Photometry


Student at Oberlin College 1885-1888

B.A. Radcliffe College 1892

References consulted

[1N N20], [5A1 DSB], [7 MWR1], [8 MBO], [9C NAW], [54 JSB], [51 MJB], [29 WWWS], [12D GKS],[www.eb.com]

Additional Information/Comments

"If Leavitt had been free to choose her own research projects, she might have investigated the consequences of the period-luminosity relationship she had discovered. ... Pickering hired people to do a specific job and didn't want them wasting their time doing anything else. "
[12D GKS]

"The standard of photographic measurements that she evolved was accepted generally among the astonomers of the world, and it was known as the Harvard Standard." [51 MJB]

Field Editor: Professor Jean Turner


Copyright © CWP and Regents of the University of California 1997 - 2001

To cite this citation:
" Leavitt, Henrietta Swan." CWP < home >


latest revision {4/30/97 mjw} 3/16/01 nb