Henrietta Leavitt's Cepheid Variable Stars

612 Words3 Pages
Leavitt’s discovery of the period-luminosity relation for Cepheid variable stars In the early 1900’s Henrietta Leavitt’s extensive research on Cepheid Variable stars enabled her to determine the relationship between the period and luminosity of stars to determine their distance from earth. Variable stars emit lights in different intensities and are also known as “lighthouse stars”. There is a direct relationship these stars have, which has a significant role in establishing the distance from earth, of stars that are in excess of 100 light years away (Mitchell, 1976, 162). This is the relationship between luminosity and the pulsation period of these stars. With luminosity being a measure of brightness and pulsation period being the time…show more content…
(Nix, 1998) This law is also related to the “inverse law” (I\r2: inverse radius), which states as the radius doubles the intensity of something (light) is quartered. i.e: if you had 2 identical candles burning at a distance of 10m and 20m respectively, you would notice that the further candle did not seem to burn as bright, having an intensity ¼ of the candle burning at 10m. It is this exact relationship that Leavitt’s was able to apply to her Period-luminosity laws. By knowing the period of a star is directly related to its absolute luminosity this law can be worked in reverse to establish distances from each other (Nix, 1998). Leavitt completed her research on period/luminosity by 1912 and astronomers such as Hubble, and Shapley have since used her work. “The period/luminosity law became the yardstick by which distances of stars could be measured by astronomers” (Nix, 1998). Without Leavitt’s work, which went unpraised and mostly unrecognised throughout her life, many of the early advances in astronomy would not have happened. References: Mitchell, Helen Buss. 1976. Henrietta Swan Leavitt and Cepheid Variables. Physics Teacher Vol.14 (3)

More about Henrietta Leavitt's Cepheid Variable Stars

Open Document