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 luminosity of a Cepheid variable star with a period of 30 days?
−5.3
Thus a 3-day period Cepheid has an absolute V-band magnitude of −3.1, while a 30-day period Cepheid has an absolute V-band magnitude of −5.3.
What is the relationship between period and luminosity of a Cepheid variable star?
Classical Cepheids exhibit a relation between period and luminosity in the sense that the longer the period of the star, the greater its intrinsic brightness; this period-luminosity relationship has been used to establish the distance of remote stellar systems.
How did Henrietta Leavitt determine the period-luminosity relationship for Cepheid variable stars?
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 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.
What is the luminosity of a Cepheid variable?
Classical Cepheid variables are 4–20 times more massive than the Sun, and around 1,000 to 50,000 (over 200,000 for the unusual V810 Centauri) times more luminous.
What is the period of this Cepheid variable in the galaxy called m101?
3 days to 50 days
Description: Cepheid variables are stars that “pulsate,” becoming progressively brighter and then dimmer at regular intervals ranging from 3 days to 50 days.
How does the period-luminosity relation compare to a Cepheid variables peak luminosity?
As Henrietta Swan Levitt discovered, a Cepheid’s variability period relates directly to its luminosity. The longer the variability period, the more luminous the Cepheid. They compare the Cepheid variable’s apparent brightness with its intrinsic brightness.
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. The event that settled the debate between Curtis and Shapley about the ‘spiral nebulae’ was.
What is the luminosity class of a star?
Luminosity class indicates, for example, whether a star is a supergiant, a giant, or a dwarf. The luminosity class is assigned by examination of the star’s spectrum, looking at luminosity-sensitive lines or line ratios. The luminosity classes generally used are:Ia–0 Extreme supergiants (sometimes called hypergiants)
What allowed Henrietta Levitt To conclude that the pulsation period of Cepheid variables was related to their intrinsic brightness?
By comparing thousands of photographic plates, Leavitt discovered a direct correlation between the time it takes for a Cepheid variable to go from bright to dim and back to bright, and how bright the star actually is (its “intrinsic brightness”). The longer the period of fluctuation, the brighter the star.
What is meant by the period-luminosity relationship of Cepheid variables explain how this can be used to measure distances?
As Henrietta Swan Levitt discovered, a Cepheid’s variability period relates directly to its luminosity. The longer the variability period, the more luminous the Cepheid. Through observations of Cepheid variables, astronomers have determined the distances to other galaxies.