Questions tagged [metallicity]

In astronomy, metallicity is a measure of how much of an object is made of elements besides hydrogen and helium.

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Why are stars made from hydrogen and helium and not other elements?

My understanding is that the stars are primarily made up of hydrogen and helium. Why do those elements end up in stars and other heavier elements make up the planets?
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Proportion of Oxygen in a typical white dwarf

What's the proportion of Oxygen in a typical white dwarf relative to the proportion of Carbon?
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How do we know the chemical composition of the crust of neutron stars?

Although neutron stars are mostly made of neutronium, the pressure at the surface is not very high which allows regular atomic matters to exist. Emission spectrum can reveal the chemical composition ...
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19 votes
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Would the emission lines of a very distant galaxy show not many traces of heavier elements as that part of the universe was very young?

Would the emission lines of a very distant galaxy show not many traces of heavier elements as that part of universe was very young? Or was there enough time for an abundance of heavier elements?
Krešimir Bradvica's user avatar
2 votes
1 answer

Can the amount of heavier elements in the Sun's core be approximated?

Can the amount of heavy and other types of elements as impurities inside the Sun's core be approximated? If these elements are present, do they disturb the process of hydrogen fusion, since they ...
Janko Bradvica's user avatar
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How does metallicity affect stellar evolution?

The main sequence evolution of a solitary star depends most of all on its initial mass. Other factors influencing its evolution are the initial metallicity, rotation and magnetism. Question: how does ...
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Why didn't heavier elements settle at the core of the solar system?

As the solar system formed, why didn't all of the heavier elements such as iron, collect where the sun is leaving the lighter elements in the outer solar system?
Rick's user avatar
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4 votes
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Why does the Sun have iron?

I read the information about 'Abundance in the Sun for the elements'. There are a lot of elements in the Sun. I thought 'how is it possible for Fe, Au, and so on to exist in the Sun ?', but I couldn't ...
정우남's user avatar
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What elements do black holes expel into relativistic jets?

What does current research say about the elements that can be created in the accretion disc of a black hole, and does the Relativistic Jet contain any of those elements? Curious as to whether the ...
Demis's user avatar
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Why is the Sun made of light elements only?

Since the entire solar system inherits its heavy elements from supernovae unrelated to our star, I fail to understand why, while capturing most of said system's matter, the sun only contain light ...
Winston's user avatar
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Why does the Drake equation never account for the abundance of the elements in the universe?

The Drake equation which is used to describe a rough estimate of possible ET civilizations that is able to communicate with us does not take into account the abundance of the chemical elements in the ...
Omar Adel's user avatar
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How is the primordial abundance of Lithium measured?

I was reading about the "Lithium problem" and I came across this Physics SE post: Discrepancy problem in lithium? The answer mentioned On the other hand, measurements of the $\rm Li$ abundance ...
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22 votes
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When will hydrogen no longer be the most abundant nucleus?

In a recent question, we learned why hydrogen is currently the most abundant nucleon or element in the universe. Here I ask a follow-up: For how long will hydrogen be the most abundant nucleus? It ...
Curt F.'s user avatar
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4 votes
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Could quasars produce elements heavier than oxygen?

I have read that supernovae are the main producers of elements heavier than oxygen. I just wonder whether quasars, which have been around a long time just like supernovae have, could have had a ...
Richard Peterson's user avatar
3 votes
1 answer

Could there be a rocky star, made from silicon, oxygen, etc?

Rocky in terms that it will have mostly silicon and oxygen composition, just like terrestrial planets. But not because it runs out of hydrogen and helium, rather it should start it's life by fusing ...
AdmiralMyxtaR's user avatar
2 votes
1 answer

Compositions of stars at different stages

So I have been trying to find what stars chemical composition is depending on the stage and I have not found anything beyond the "average star" or our sun. For example out the sun and many others ...
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28 votes
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Can elements heavier than iron be present in a star's core?

My understanding is that elements heavier than iron and nickel are not formed in a star but, can heavy elements such as lead and others be present/found in a star's core ? I ask because the following ...
ScienceAmateur's user avatar
-2 votes
2 answers

Is it possible that there are stars working on fission?

Most/all stars are getting their energy from fusion of small atoms like our sun. But is it possible according to the laws of physics that there are stars getting their energy from fission fe with ...
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1 vote
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Stellar classifiaction and metals

I have recently started to study astronomy and there is a thing with stellar classifications I can't get my head around: The colder the star the more absorption lines from metals are present in its ...
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Why do astronomers call all elements heavier than helium "metals"?

I understand that a scientific term need not be constrained by its etymology. But is there some significant reason why astronomers choose to call all elements heavier than helium "metals"? Are ...
Colin McLarty's user avatar
2 votes
2 answers

How much of an asteroid mass can be in platinum or rare metals?

There are many articles about the 2011 UW-158 asteroid which will pass earth tonight. The interesting thing about this asteroid is that it is said to contain $5.4 trillion worth of platinum. Many ...
Abanob Ebrahim's user avatar
2 votes
1 answer

Discrepancy problem in lithium?

Why is there a discrepancy between the amount of lithium-7 predicted to be produced in Big Bang nucleosynthesis and the amount observed in very old stars?
Mohit Sinsinwar's user avatar
32 votes
4 answers

Metal-rich star formation

While discussing star formation on cosmological scales with some classmates, we mentioned the breakdown between the different stellar populations via metallicity: Population III: $Z = [{\rm Fe/H}] \...
Kyle Kanos's user avatar
11 votes
2 answers

Storing a Planet-sized Chunk of Metal Inside a Star

Would it be physically possible to "store" a planet-size or larger sum of metal, say gold or platinum, inside a star by letting it fall to the core? Would it be possible to detect which stars had ...
Sam Washburn's user avatar
3 votes
2 answers

How did all of the heavy elements on earth get here?

I have often read that a first generation star went supernova and seeded our solar system. It is well known that stars that go supernova are the source of elements heavier than iron. I guess I am ...
Carlos's user avatar
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8 votes
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How to explain the existence of heavier elements in Population I stars and in Population II stars contain lighter one

Recently I read Astrophysics Notes where I found a statement that young stars are classified as Population I stars and relatively older one as Population II stars. Population I stars contain ...
Radha Krishna's user avatar
4 votes
2 answers

Stellar Activity Cycle versus Metallicity

Our Sun exhibits sunspot max/mins on about a 11 year period. It's a G2 spectral class on the HR Diagram. We know that some stars exhibit "starspot" cycles of various intensities and periods. These ...
Michael Luciuk's user avatar
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How close are humans to creating gold from other elements?

Gold is made in supernovae. How close are humans to doing that? Or is it even possible to do that unless gravity is absurdly high?
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17 votes
5 answers

Age of the Earth and the star that preceded the Sun

One of the great unheralded advances made in the history of science was the ability to determine the age of Earth based on the decay of isotopic uranium. Based on the apparent abundance of uranium in ...
Humble's user avatar
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37 votes
6 answers

How many times has the matter in our Solar System been recycled from previous stars?

I've got a basic understanding of these facts: The Universe is a little over 13 billion years old. Our Galaxy is almost that old. Our Solar System is roughly 4.6 billion years old. The heavier ...
Clinton Pierce's user avatar
28 votes
3 answers

Why the distribution of elements on Earth?

I've been wondering exactly why the elements are distributed the way they are on Earth. The heavier elements have their origins in the centers of stars, or in supernovae. After the death of the stars, ...
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