What is the relationship between period and luminosity in Cepheid variables?
Cepheids are special in that the period at which Cepheids pulse is related to their average intrinsic luminosity. More luminous Cepheids pulse more slowly. By measuring the period of a Cepheid we can calculate its intrinsic luminosity, and thus its distance.
What is the period of a Cepheid variable related to?
Cepheid variable, one of a class of variable stars whose periods (i.e., the time for one cycle) of variation are closely related to their luminosity and that are therefore useful in measuring interstellar and intergalactic distances.
What is the relationship between period and luminosity?
In astronomy, a period-luminosity relation is a relationship linking the luminosity of pulsating variable stars with their pulsation period. The best-known relation is the direct proportionality law holding for Classical Cepheid variables, sometimes called the Leavitt law.
How do you find the luminosity of a Cepheid variable?
Using Cepheid Variables to Measure Distance Once the period of a distant Cepheid has been measured, its luminosity can be determined from the known behavior of Cepheid variables. Then its absolute magnitude and apparent magnitude can be related by the distance modulus equation, and its distance can be determined.
What is the period-luminosity relationship quizlet?
The period-luminosity relationship discovered by Henrietta Leavitt for Cepheid variable stars, relating variability to over-all brightness says that. the shorter the period, the lower the luminosity of the star.
What is the period-luminosity relationship discovered by Henrietta Leavitt?
The brighter the star is overall, the longer the period of luminosity. Since the cepheids in the Magellanic Clouds were all about the same distance from Earth, Leavitt concluded that the period, or time it took to complete one cycle of dimming and brightening, was related to the star’s magnitude, not distance.
What is one of the differences between Cepheids and RR Lyrae variables?
Cepheids are higher luminosity stars than RR Lyrae variables, and have longer periods. Cepheids are higher luminosity stars than RR Lyrae variables, and have longer periods.
Who discovered the period-luminosity relationship?
Henrietta Swan Leavitt
Henrietta Swan Leavitt, (born July 4, 1868, Lancaster, Massachusetts, U.S.—died December 12, 1921, Cambridge, Massachusetts), American astronomer known for her discovery of the relationship between period and luminosity in Cepheid variables, pulsating stars that vary regularly in brightness in periods ranging from a …
Why is the period-luminosity relationship important quizlet?
Henrietta Swan Leavitt discovered the period-luminosity relationship. This relationship is critical because it tells us the longer the pulsation period, the more luminous the star.
What is special about Cepheid variable stars?
Cepheids Variables are special type of variable star in that they are hot and massive – five to twenty times as much mass as our Sun – and are known for their tendency to pulsate radially and vary in both diameter and temperature.
Who discovered the period-luminosity relation?
galaxies. …he made use of the period-luminosity (P-L) relation discovered by Henrietta Leavitt of the Harvard College Observatory.
Who discovered period-luminosity relationship for Cepheid variables?
A Science Odyssey: People and Discoveries: Leavitt discovers a correlation between Cepheids’ period and luminosity.
By intense observation and mathematical calculation, Leavitt realized that with cepheid variable stars (which change brightness with great regularity), there is a direct correlation between a the longer the period of luminosity. Since the cepheids
What is period luminosity?
Period-Luminosity relation for Classical Cepheid variables In astronomy, a period-luminosity relation is a relationship linking the luminosity of pulsating variable stars with their pulsation period. The best-known relation is the direct proportionality law holding for Classical Cepheid variables, sometimes called Leavitt’s law.
What are Cepheid variables?
Classical Cepheids include: Eta Aquilae,Zeta Geminorum,Beta Doradus,RT Aurigae,Polaris,as well as Delta Cephei.
What is the equation for luminosity?
To get the total radiated luminosity (say in Watts), you multiply this P by the surface area of the star, which is A = 4πR^2. Try calculating this for the sun, which has a surface temperature of about 5600 K. This should give you the luminosity of the sun in Watts.