# Tag Info

31

There is basically an upper limit to the mass of a star because their luminosity is so great that the radiation pressure prevents the accretion of further mass. However, the upper limit depends on the composition of the accreting material. This is because the effect of the radiation depends on the opacity of the material - stuff that is more metal-rich is ...

14

Starting from a protostar, one would hope to be able to predict everything about its future development if we knew its initial mass, chemical composition and angular momentum. Mass is fundamental because it determines how much fuel the star will have and the pressure at its core. Composition is key because among other things it determines the opacity of the ...

7

Rob Jeffries has covered pretty much everything in his answer, but I'll add that this is a question with a long history, enough that there is a famous answer to it called the Russell-Vogt or Vogt-Russell Theorem. That states that composition and mass are the two key properties, assuming that the star is in hydrostatic equilibrium and derives its energy from ...

4

If I understand correctly, you are trying to create a realistic looking view of the stars rendered (in the game) on a dome surrounding the game play area. So you don't need to fly through the stars or interact with them in a 3D environment, is that right? If so, it isn't the star size you want to reproduce - it is the brightness. We can't see the width of ...

3

The color index of the star can give you that information. I can look it up for you if I know which exoplanet you're interested in, or you can find it in the NASA Exoplanet Database here.

3

According to Lodders (2003, https://arxiv.org/pdf/1010.2746 ) the relative abundance of helium to hydrogen is $A({\rm He})=10.925$, on a logarithmic scale where the hydrogen number abundance is 12. So this would mean a helium to hydrogen ratio, by number, of $10^{10.925-12}=0.08414$. i.e. 8.4% (your source uses 10.93, not 10.99, hence a very slightly ...

1

At the heart of this question is a fundamental misunderstanding of the way gravity works in a (near) frictionless environment, such as space. Gravity pulls objects directly towards each other, which will act to slow their motion apart, or speed their motion together. However it has no effect at all on any motion at right angles to the line joining them. So ...

1

It can tell you the chemical composition of the star. what elements are present and this can help you tell other things about the star. For example, the oldest stars are metal poor meaning they formed earlier in the history of the universe. Younger stars are expected to have more metal in them. Also the energy of the spectral lines of the elements are well ...

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