Skip to main content
Astronomy

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

4
  • 1
    $\begingroup$ Thank you. I have another question then: The Earth has a large iron core. How was all that iron dust produced that it formed from? When a star dies, as I understand the core (where iron the final fusion product is) is left behind, as fusion is occurring in a shell around it in the late stages. Or is that incorrect? $\endgroup$
    – P Varga
    Commented Feb 7, 2019 at 13:31
  • 4
    $\begingroup$ Iron can get out of a star in several ways, often involving a supernova. Then the iron collects in the solar nebula as a trace component. It's still mostly hydrogen gas, but the hydrogen gas doesn't stick together in the dust, so dust picks out elements like iron, silicon, and other components of the Earth. Planets close to the Sun have especially high iron content, because iron has a high melting point so it can stick together even if it's hot. $\endgroup$
    – Ken G
    Commented Feb 7, 2019 at 17:16
  • 1
    $\begingroup$ Iron white dwarfs? No. What do you mean by a smaller radius for its gravity? Most stellar mass white dwarfs are a similar size to the Earth. $\endgroup$
    – ProfRob
    Commented Feb 8, 2019 at 7:11
  • 1
    $\begingroup$ I was talking about the core of the Earth, which is smaller than a white dwarf, and I gave the reason for that. Yes, I know most people have not realized this, you have to think about it. As for iron in white dwarfs, I did not mean to imply the entire white dwarf would be iron,only it's core, and I expect this would be rare, but not impossible: adsabs.harvard.edu/abs/2017ApJ...848...11B states "We further identify a few white dwarfs that are possibly composed of an iron core rather than a carbon/oxygen core, since they are consistent with Fe-core evolutionary models." $\endgroup$
    – Ken G
    Commented Feb 8, 2019 at 14:06