# Tag Info

18

After H burning has finished, the he mass of the He core gradually increases, as does its density and temperature. Low-mass stars have denser cores when they reach a temperature at which He is ignited. The density is high enough that the electrons in the core are degenerate. In such conditions the heat from the nuclear reactions goes almost exclusively into ...

7

TL;DR: 1000 K (according to differentiated model of Pluto) According to the density value of Pluto, astronomers proposed three types of structural models: Undifferentiated or "cold" model: rocks mixed with water-ice Differentiated or "hot" model: rocky core and water-ice mantle Rocky core only (temperature high enough to boil off water-...

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More massive stars indeed have higher pressures, but what's key is that they also have higher temperatures. After leaving the main sequence, they reach core temperatures of a few times $\sim10^8$ Kelvin while their densities remain at something like $\sim10^4$ g cm$^{-3}$ - which, you can check, is within the nondegenerate regime. Therefore, helium fusion ...

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Massive stars do not undergo helium flash because they have core temperatures high enough to prevent the helium core from becoming electron-degenerate. Check here for some more information. Therefore, the star can burn helium in a smooth transition, instead of undergoing helium flash. In more details, the massive star's core heats up past the helium burning ...

2

Scientists (and science fiction writers) have speculated about the possbilities of life under the surfaces or on the surfaces of large moons in our solar system or large exomoons of large exoplanets in other star systems. So a good place to find any limits on the possible properties of moons that can have magnetic fields is a scientific discussion of the ...

1

Even if the moon weighed twice as much as our planet, given a rotation of 27 days it wouldn't have a major geodynamo, which is proportional to mass, rotation speed and electromagnetic constituents. It has to have higher rotation speed and a lot of iron at the core. The moon's rotation is nearly zero, or once every 27 days compared to our 24 hours. In 2010, a ...

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I think this question might trigger more an open-ended discussion, than a definitive answer, but let me try my take on it. Firstly, Is it more likely that one of these collided with Jupiter itself at the head-on angle needed for the core-warping collision? In order to collide, a co-orbital configuration is more favourable than a orbit-crossing encounter at ...

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