The important feature of a Cepheid Variable that allows it to be used for distance measurements is that its period is related directly to its luminosity . This relation allows us to work out how much brighter than the Sun the star is.
Why are variable stars important?
Research on variable stars is important because it provides information about stellar properties, such as mass, radius, luminosity, temperature, internal and external structure, composition, and evolution. Some of this information would be difficult or impossible to obtain any other way.
Why are Cepheid variables important quizlet?
Why are Cepheid variables important in astronomy? Cepheids variables are pulsating stars whose pulsation periods are directly related to their true luminosities. Therefor they can be used as distance indicators.
What is the significance of Cepheid variable stars in determining distances quizlet?
Cepheid variable stars are useful to find the distances of the galaxies because their periods and luminosity are nearly related.
Why is the Hyades cluster important for building?
Why is the Hyades Cluster important for building up a catalog of the true luminosities of main-sequence stars? It is close enough to us that the distance to the cluster stars can be found by stellar parallax. How did Edwin Hubble measure the distance to the Andromeda Galaxy?
What do variable stars help astronomers determine?
Like all variable stars, Cepheids exhibit a variable brightness. … Through observations of Cepheid variables, astronomers have determined the distances to other galaxies. They compare the Cepheid variable’s apparent brightness with its intrinsic brightness.
Why are pulsating variable stars important to astronomers?
Pulsating variable stars are intrinsic variables as their variation in brightness is due to a physical change within the star. … The study of pulsating variables is of great importance to astronomers. Analysis of light curves provides vital information about the interior processes in stars.
What are RR Lyrae and Cepheid variable stars and why are they important to understanding the universe?
Cepheids and RR Lyrae stars are two types of pulsating variable stars. … RR Lyrae stars can be used as standard bulbs, and cepheid variables obey a period-luminosity relation, so measuring their periods can tell us their luminosities.
What important role do Cepheid variables stars have in astronomy quizlet?
Variable stars such as Cepheid variables are used in what important measurement in astronomy? distance, particularly to nearby galaxies. their luminosity, or absolute magnitude, and their pulsation period. interstellar dust that obscured the more distant stars and thereby localized his observations.
Why are variable stars good distance indicators?
Why are Cepheid variable stars good distance indicators? Cepheid stars period is related to their luminosity. With that you can find its apparent magnitude and with that you can find distance. … They reach the same maximum at explosion, they compare this to the known luminosity to get distance.
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.
What was Henrietta Leavitt’s most important contribution to astronomy?
Leavitt is best known for discovering about 2,400 variable stars between 1907 and 1921 (when she died). She discovered that some of these stars have a consistent brightness no matter where they are located, making these so-called Cepheid variables a good measuring stick for astronomical distances.
What are Cepheids used for?
Cepheids, also called Cepheid Variables, are stars which brigthen and dim periodically. This behavior allows them to be used as cosmic yardsticks out to distances of a few tens of millions of light-years.
What did the Cepheid variable stars help Hubble find?
These variable stars help astronomers calculate distances to other galaxies. … Astronomer Edwin Hubble used these Cepheid variable stars to discover that the more distant a galaxy is from Earth the faster it moves away. There is a proportionality between the distance to a galaxy and its recessional velocity.
What relationship allows astronomers to easily calculate distances for Cepheid variable stars?
Measuring the apparent magnitude of a Cepheid then allows us to determine its distance using the period-luminosity relationship.
Why are stars like RR Lyrae variables so important in our efforts to determine distances?
Because Cepheids are so luminous, they can be seen to large distances. Parallaxes can be used to determine distances to 500 parsecs or so. … RR Lyrae stars can also be used to measure distances, but since they are less luminous, they can only be seen to smaller distances.
How do astronomers measure the distance to a periodic variable star?
By observing the apparent luminosity, dimmed by the inverse square law of light traveling across the vast reaches of space, and comparing this with the predicted luminosity, astronomers can calculate the distance to that star. …
Can variable stars be used to determine the distance to globular clusters?
Type II Cepheids (also termed Population II Cepheids) are population II variable stars which pulsate with periods typically between 1 and 50 days. … Type II Cepheids are used to establish the distance to the Galactic Center, globular clusters, and galaxies.
Why is knowing the cosmic distance to a star so important for us to be able to determine a star’s luminosity?
As before, if we know how luminous the star really is and see how dim it looks, the difference allows us to calculate its distance. … Nearby stars thus serve as benchmarks for more distant stars because we can assume that two stars with identical spectra have the same intrinsic luminosity.
What makes white dwarf supernovae useful to astronomers?
What makes white dwarf supernovae useful to astronomers? … They are much brighter than massive star supernovae and can be used to locate distant galaxies.
What is the most accurate way to determine the distance to a relatively nearby star within the Milky Way?
It’s called “parallax”. Basically you look at how much the star appears to move in the sky as a result of the earth actually moving on its orbit aroun the sun; the more the star seems to move the closer it is.
Why are white dwarf supernovae more useful?
Why are white dwarf supernovae more useful than massive star supernovae for measuring cosmic distances? White dwarf supernovae all have roughly the same true peak luminosity, while massive supernovae come in a wide range of peak luminosities.
What can we learn from Hubble’s law?
Hubble’s law, which says simply that a galaxy’s velocity (or as is sometimes plotted, its redshift) is directly proportional to its distance, also tells us something important about the state of the universe. If the universe is static and unchanging, there should be no correlation between distance and velocity.