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Questions tagged [metal]

Any element other than hydrogen and helium is considered a metal by astronomers.

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12 votes
3 answers
1k views

Why can't a quasistar exist now?

From my research, I found out that quasistars theoretically existed because of a black hole core whose radiation pressure counteracted gravity within the star. However, a few websites stated that ...
Pyrania's user avatar
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26 votes
1 answer
5k views

Is lithium considered a metal in astronomy?

My lecture notes are conflicting on this issue so I seek definitive clarification. In Astronomy, are metals either A: the elements which form within stars (i.e., not Big Bang nucleosynthesis, where ...
zabop's user avatar
  • 481
5 votes
3 answers
5k views

Metal distribution in our solar system

The sun dominates in our solar system. I wonder whether in every aspect the sun plays the most important role in our system. For example, all kinds of metals are mainly located in the sun instead of ...
questionhang's user avatar
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5 votes
2 answers
813 views

Why are stars more metallic closer as you move closer to the galactic bulge?

As I see it, most of the stars in the galactic bulge are Population I stars. However, as one moves farther from the galactic bulge, star metallicity decreases. In fact, halo stars are almost entirely ...
Sir Cumference's user avatar
9 votes
2 answers
4k views

Why you use log to measure metallicity in galaxies?

For example, I saw the next expression for matallicity in a paper: $\log(O/H) + 12$. I understand O/H is the O(Oxygen) to H(Hydrogen) ratio but why is there the number 12? And why the logarithm?
Aaron-S's user avatar
  • 99
6 votes
1 answer
508 views

Why could Quasi-stars ("black hole stars") have only existed when everything was hydrogen and helium? (no metal "contamination")

This informative answer to What was the absolute limit to the possible sizes of the first stars formed from “primordial material with no metals”? led me to Wikipedia's Quasi-star; Formation and ...
uhoh's user avatar
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