What is the relationship between luminosity and period?
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.
What is the relationship between the brightness and period for Cepheid variable stars?
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.
What is the period of a Cepheid variable?
The classical Cepheids have periods from about 1.5 days to more than 50 days and belong to the class of relatively young stars found largely in the spiral arms of galaxies and called Population I. Population II Cepheids are much older, less luminous, and less massive than their Population I counterparts.
What is the luminosity of a Cepheid variable?
300 to 40,000 L
Cepheid variables have the following properties: Period = 2 to 60 days. Average Temperature = about 6000 Kelvin. Average Luminosity = 300 to 40,000 L.
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.
Who discovered the period-luminosity relationship?
Henrietta Swan Leavitt
Discovered in 1908 by Henrietta Swan Leavitt, the relation established Cepheids as foundational indicators of cosmic benchmarks for scaling galactic and extragalactic distances.
For what type of object is the period-luminosity relation used for determining distances?
For what type of object is the period-luminosity relation used for determining distances? Cepheids. The region on the H-R diagram where pulsating variables occur is called the: Instability strip.
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.
Who discovered the period-luminosity relationship and why was it so critical?
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 did Henrietta Swan Leavitt discover for Cepheids quizlet?
In 1908 Henrietta Swan Leavitt discovered that for Cepheids, the brighter variables have the longer periods. Cepheids are important because the period, which is easy to determine, allows the absolute magnitude to be determined. In 1908 she discovered that for Cepheids, the brighter variables have the longer periods.
Who discovered the period-luminosity relationship in Cepheid variables?
astronomer Henrietta Leavitt
In the early 1900s, astronomer Henrietta Leavitt discovered an odd but powerful fact about one class of variable stars, which are known as Cepheid variables after their prototype star, Delta Cephei.