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adkinje
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Is it correct that the age of a star, such as the sun, is calculated by measuring the amount of helium made from fusion? If so, how do we know if that the star didn't form from a cloud that already had helium in it?
twofish-quant said:Also this also means that when the geologists say ooppss... We thought that the meteorites said that the solar system was 4.7, but not we think that it's 4.52, that people go in and tweak their models to match the new age.
The sun is really important since we have a huge amount of information about it so people need to change their models so that when you put in the sun, you get the right numbers. One thing that gives us huge amounts of information is astroseismomology which sees how sound waves goes through the sun and can get us temperature and density profiles.
http://www.ap.stmarys.ca/~guenther/Level01/solar/what_is_ssm.html
Chronos said:Mass and composition determines stellar ages. The age estimate becomes pretty good once you nail those properties down.
AdkinsJr said:It seems that astrophysicists have accurately measured the age according to the abstract of this paper.
twofish-quant said:Not really. What you do is to run computer simulations to see how the star changes over time. It's rather difficult to use this to measure the age of a single star, and this is most useful when you have a lot of different stars that are at in a cluster.
The amount of helium for a star doesn't change that much because all of the helium that the sun creates is still buried in the center of the star. We can tell that the sun is a third or fourth generation star because its surface contains heavy elements that the sun did not create.
The main limits on the age of the sun come from radioactive measurements of meteorites.
AdkinsJr said:Is there any way to know if the heavier elements were present when the sun formed? Isn't it possilbe that they could have been transported to the sun via asteroids, comets, etc. after it had already formed?
Scientists calculate the age of stars by using the star's mass, luminosity, and temperature. These parameters are compared to theoretical models of stellar evolution to determine the age of the star.
Helium is significant in calculating the age of stars because it is the second most abundant element in stars and its abundance changes over time as the star evolves. By measuring the amount of helium in a star, scientists can estimate its age.
Helium abundance in stars is typically measured by analyzing the absorption lines of helium in the star's spectrum. These lines are compared to theoretical models to determine the amount of helium present in the star.
No, helium abundance can only be used to determine the age of low-mass stars. High-mass stars have shorter lifespans and their helium abundance is not a reliable indicator of their age.
The accuracy of age calculations using helium abundance depends on the quality of the data and the specific method used. In general, age estimates can have uncertainties of a few million years for low-mass stars and up to a few hundred million years for high-mass stars.