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triabva2003
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Why giant stars are so low in density?
triabva2003 said:Why giant stars are so low in density?
It has nothing to do with less gravity. The core becomes super heated in ancient stars - which means more pressure on the outer layers. Stars are in a continuos state of hydrostatic equilibrium - until the core temperature becomes too hot or cool to remain in gravitational balance.Radrook said:By the time they become giants they have burnt up a lot of their fuel and their outer layers have bloated due to less gravity. It doesn't mean that their cores aren't very dense though. It just means their average density is lower than main sequence stars which are still fusing hydrogen and have enough gravity to keep their outer layers compact..
Chronos said:It has nothing to do with less gravity. The core becomes super heated in ancient stars - which means more pressure on the outer layers. Stars are in a continuos state of hydrostatic equilibrium - until the core temperature becomes too hot or cool to remain in gravitational balance.
Giant stars are low in density because they have reached the end of their life cycle and have started to expand. As they expand, their outer layers become less dense, resulting in a lower overall density.
Giant stars are much less dense than smaller stars. This is because smaller stars have not yet reached the end of their life cycle and are still burning hydrogen in their cores, which keeps their outer layers more compact.
No, giant stars cannot become more dense over time. As they expand and cool, their density decreases even further.
Yes, the low density of giant stars does affect their lifespan. As their density decreases, their surface temperature also decreases, causing them to burn through their remaining fuel at a faster rate. This results in a shorter lifespan for giant stars compared to smaller stars.
Yes, the composition of a star can also affect its density. Giant stars with higher amounts of hydrogen in their outer layers will have a lower density compared to stars with a higher proportion of heavier elements like carbon and oxygen.