How to Use Variable Stars to Calculate Distance in the Universe
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- Опубликовано: 27 авг 2024
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Welcome, my name is Phil, and in this video I discuss how variable stars can be used to calculate distances in the Universe.
Variable stars, with their inherent variability in brightness, serve as invaluable cosmic yardsticks for astronomers. By studying the periodic fluctuations in their luminosity, astronomers can establish a direct relationship between their intrinsic brightness and their observed luminosity. This relationship, known as the period-luminosity relationship, provides a reliable means to gauge the distance to variable stars and, consequently, to objects located within their vicinity.
One notable class of variable stars, Cepheid variables, has played a pivotal role in cosmic distance measurement. These stars exhibit a distinctive pattern of brightening and dimming over a regular period, directly correlated with their intrinsic luminosity. By comparing the observed brightness of a Cepheid variable with its known intrinsic luminosity, astronomers can accurately determine its distance from Earth, thereby enabling precise measurements of distances to far-flung celestial objects.
Additionally, another class of variable stars, known as RR Lyrae variables, offers further insights into cosmic distances. These stars, found predominantly in globular clusters and certain types of galaxies, display a predictable relationship between their period of variability and their luminosity. Leveraging this relationship allows astronomers to gauge the distances to these stellar clusters and galaxies, providing crucial information for understanding the vast scales of the universe. Thus, through the meticulous study of variable stars and their unique luminosity behaviors, astronomers can unravel the spatial dimensions of our cosmic neighborhood and beyond.
When we sub in a value for the apparent magnitude do we use the peak apparent magnitude or the minimum?
Probably use the average, or mid magnitude
Ah thank you!!! I thought so just wanted to make sure. Thanks for the help you explained it well
@dannyhodson2525 thanks, glad it helped!
you kinda lost me after we found the period ( which if I understand correctly is found by measuring the high and low of a cepheid)
but all still pretty impressive how astronomers come up with these solutions.
Yes that is right, you measure the time it takes from its maximum brightness to the next maximum brightness. It is really impressive what you can learn just from how bright a star is and how it changes over time.
exactly, he explained nothing about how to measure distance