The importance of the study of RR Lyrae stars is at least threefold: first they can be used as "standard candles" in distance determinations, and secondly they provide us with information on the chemical composition (helium and heavy element abundance) in the halo and old disk popula- tion of our galaxy.
- Why are RR Lyrae stars useful?
- Why are variable stars useful?
- Why are Cepheid variable stars useful for finding the distances to galaxies?
- What is the most important important difference between Cepheids and RR Lyrae variable stars?
- What important measurement did RR Lyrae variables allow astronomers to get?
- What is common among all RR Lyrae stars quizlet?
- Why are Cepheid variable stars important in our study of the Milky Way galaxy?
- How do astronomers measure the distance to RR Lyrae stars?
- How can variable stars be used to determine distance?
Why are RR Lyrae stars useful?
RR Lyrae stars are found at all galactic latitudes, as opposed to classical Cepheids, which are strongly associated with the galactic plane. Because of their old age, RR Lyraes are commonly used to trace certain populations in the Milky Way, including the halo and thick disk.
Why are variable stars useful?
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 variable stars useful for finding the distances to galaxies?
Using Cepheid Variables to Measure Distance Cepheid variables are extremely luminous and very distant ones can be observed and measured. Once the period of a distant Cepheid has been measured, its luminosity can be determined from the known behavior of Cepheid variables.
What is the most important important difference between Cepheids and RR Lyrae variable stars?
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. Compared to the Milky Way, how many stars are contained in the most massive galaxies?
What important measurement did RR Lyrae variables allow astronomers to get?
RR Lyrae stars make it easy to determine the distance to another galaxy. Just measure the average apparent magnitude of the variables, and compare the known absolute magnitude. A typical RR Lyrae has a luminosity perhaps 50 times greater than the Sun.
What is common among all RR Lyrae stars quizlet?
RR lyrae stars have what in common? they have the same luminosity curve with periods from half to one day.
Why are Cepheid variable stars important in our study of the Milky Way galaxy?
Why are Cepheid variable stars important in our study of the Milky Way galaxy? Cepheid variable stars are stars that periodically brighten and dim. Their brightness periods can be used to determine their distance, which is useful for astronomers studying the distance of the Milky Way galaxy.
How do astronomers measure the distance to RR Lyrae stars?
RR Lyrae stars make it easy to determine the distance to another galaxy. Just measure the average apparent magnitude of the variables, and compare the known absolute magnitude. A typical RR Lyrae has a luminosity perhaps 50 times greater than the Sun.
How can variable stars be used to determine distance?
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. The difference between observed and actual brightness yields the distance.