Questions tagged [metallicity]

Questions regarding the fraction of metal to non-metal elements, with metals being elements other than hydrogen and helium.

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How does metallicity change the mass-radius and mass-luminosity relations in main-sequence stars?

I'm building a star cluster for my space opera setting and I'd like to include some highly-metallic stars as anomalies and resources. Wikipedia defines stellar metallicity as the fraction of a star's ...
TerranAmbassador's user avatar
1 vote
1 answer
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Why does the metallicity of stars decrease with increasing galactocentric radius and height above the galactic plane?

Metallicity decreases with the Galactocentric radius and height above the Galactic plane (Bergemann et al. 2014; Duong et al. 2018). https://www.aanda.org/articles/aa/abs/2014/05/aa23456-14/aa23456-14....
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Large dataset of galaxies redshift, mass, and metallicity?

I'm curious if there is a standard dataset for redshift-mass or redshift-metallicity like there is for redshift-distance with Pantheon+SH0ES. https://github.com/PantheonPlusSH0ES/DataRelease/tree/main/...
MikeHelland's user avatar
2 votes
3 answers
179 views

Is there a link between a star's metallicity and the availability of chemical elements in its system?

Considering aspects of interstellar trade for worldbuilding purposes, I'm researching what resources might be available in each star system. The premise is that if one star system has an abundance of ...
Krišjānis Liepiņš's user avatar
3 votes
1 answer
220 views

Could macroscopic primordial black holes have created metals shortly after the big bang?

After seeing articles about the JWST like these two: https://news.cornell.edu/stories/2023/02/astronomers-discover-metal-rich-galaxies-early-universe https://www.livescience.com/james-webb-space-...
Nathan Stanton's user avatar
6 votes
1 answer
293 views

Which star has the highest known metallicity?

Which star has the highest known metallicity? The highest I know of is Sirius Which a Metallicity of +0.5, which corresponds to have a Ratio of Fe to H 3 times that of the sun.
blademan9999's user avatar
22 votes
2 answers
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Do stars become more metal-rich as they evolve?

Since we determine the metallicity of a star ([Fe/H] or Z) from surface emission, does this change as it ages? For instance, can a young star with a measured [Fe/H] of -0.02 have a higher value when ...
Jack R. Woods's user avatar
6 votes
1 answer
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How does metallicity reduce the likelihood of black hole formation?

Large stars collapse and if they are large enough form black holes. But the likelihood reduces with metallicity. What mechanism facilitates this? I believe it has something to do with opacity and ...
TheJeran's user avatar
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What physical process can Metallicity(Z) of a galaxy tell us?

For example, if there is a galaxy and its metallicity increase or decrease from high redshift to present day (We can see it from simulation like TNG or EAGLE). What physical process we can know? ...
Jinning Liang's user avatar
3 votes
1 answer
725 views

Conversion of oxygen abundance to metallicity

How can you convert oxygen abundance values (12+log(O/H)) to metallicity values z. Like oxygen abundance of 8.69 is a metallicity of about 0.02 (solar metallicity). Thus, given a random abundance ...
SlightDecoy's user avatar
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How to calculate metallicity of a star that is made of iron of 20kg and Hydrogen 1000 kg?

I want to know how to calculate star metallicity using only masses of metal and hydrogen of the star. I am attaching my working so far. I am not sure how to exactly calculate the log10(Fe/H) based on ...
Jerome's user avatar
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What happens to the non-fusion formed metals in stars?

Let’s consider a population I star of some given metallicity. I know that depending on the type of star, different structures are possible with convection zones and radiative zones trading around ...
Justin T's user avatar
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9 votes
1 answer
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Metallicity in gravitational wave astronomy

Metallicity relates to the quantity of elements in an object that are heavier than hydrogen and helium. I often see this terminology in recent studies of gravitational waves such as this paper. If I ...
Junaid Ihsan's user avatar
8 votes
1 answer
599 views

Define stellar metallicity

It is quite common to list metallicity for stars. For example for Teegarden's star, notable because one of its two planets (b) has an Earth similarity index of 0.95, the highest listed on the ...
Carl's user avatar
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1 answer
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Why is the carbon/oxygen ratio at low metallicities important to study?

Oxygen and carbon are the most abundant elements in the Universe (formed via stellar nucleosynthesis), following only hydrogen and helium (formed via the Big Bang). There seems to be a lot of work to ...
quantumflash's user avatar
8 votes
1 answer
863 views

Why does metallicity increase the opacity inside stars?

A vague answer I've seen is that it has something do with a greater number of possible excited states, but I don't know what this means for a partially ionized plasma - much less a fully ionized ...
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Is there a metallicity threshold past which star formation is impossible?

I've learned that metallicity is a very important factor to consider when talking about a star's formation and lifecycle. That gets me wondering whether a high enough metallicity could prevent the ...
zucculent's user avatar
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Why do we talk about metallicity in stars instead of more specific elements?

Metallicity is important to a star's evolution, but why don't we talk about the abundance of specific elements? I don't imagine that the effect on a star's evolution would be the same if a its ...
zucculent's user avatar
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13 votes
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Is oxygen an alpha element?

Type II (core-collapse) supernovae occur shortly after star formation and enrich a galaxy with $\alpha$ elements such as O, C, NE, Mg, Ca and Si. On the other hand, Type Ia supernovae occur on a more ...
quantumflash's user avatar
3 votes
0 answers
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Strength of core-envelope coupling in stars (again)

I asked this on the physics SE but it received little attention: Consider a high-mass zero-age main-sequence (ZAMS) (e.g., $m_{\rm ZAMS} \gtrsim 30\,$M$_{\odot}$) star. I understand that the core-...
Daddy Kropotkin's user avatar
1 vote
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How do you correct the Period-Luminosity relationship for metallicity?

Refer to the link: https://www.astro.utoronto.ca/DDO/research/cepheids/cepheids.html Tha author has used the relationship $M_V=-2.902log(P)-1.203$. It is mentioned that this is not corrected for ...
Kushagra's user avatar
6 votes
1 answer
485 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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Are metallicities of molecular clouds lower in the outskirts of the galaxy?

(this question was originally posted in an answer by user PSR-1937-21 to another post. I find it an interesting one, but since they don't seem to be active anymore, I'm posting it to see if somebody ...
SE - stop firing the good guys's user avatar
6 votes
1 answer
388 views

Have any planetary systems been found around Population II stars?

I always understood that Population II stars were unlikely to have planets as they were virtually all H and He with very little else. Have recent observations confirmed this, or have planets been ...
Mike Stone's user avatar
5 votes
1 answer
2k views

How to evaluate the fit of an isochrone to a stellar population?

Consider that I know the extinction, distance modulus, reddening, and metallicity for a particular star cluster. I need to determine it's age from isochrone fitting. After generating the required ...
Hrsht's user avatar
  • 333
6 votes
1 answer
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Formation of the First Stars

I've got a few questions about the first stars to form in the universe. First off how might metalicity have impacted the formation of the first stars and also what effect would the absence of metals ...
PSR-1937-21's user avatar
4 votes
2 answers
1k views

Why is the metallicity of elliptical galaxies low?

As far as I understand, metallicities of old stars are usually low and those of new stars are usually high. If elliptical galaxies form after merger of galaxies, then surely that means the elliptical ...
S R Maiti's user avatar
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3 votes
1 answer
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Why the forbidden lines of [OIII],[NII] and [SII],[OII] are sensitive to electron temperature and electron density, respectively?

I am trying to understand the topic of "Metallicity estimates", either HII regions or planetary nebula. For this latter, the electron temperature (and density) must be known. I am studying the ...
Luis Enrique Garduño Puga's user avatar
2 votes
1 answer
77 views

What was the "optical illusion" that led to erroneous metal concentrations in stellar atmospheres in the galactic center?

Articles summarizing a recent result about certain heavy element concentrations in stars near the galactic center all say that earlier reports about high levels in stellar atmospheres were the product ...
uhoh's user avatar
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2 votes
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What's the profound reason(s) why the star formation rate drives the scatter of the mass-metallicity relation in galaxies?

Since decades it's well known that a correlation between stellar mass and metallicity (Z; both stellar and gas-phase Z, but here I focus on the gas-phase Z) exists (e.g., Tremonti+04; analysis of >...
user avatar
7 votes
2 answers
4k views

Correct relation between metallicity (z) and iron content ([Fe/H])

The Wikipedia entry on Metallicity states that: $\log_{10}\left(\frac{Z/X}{Z_\mathrm{sun}/X_\mathrm{sun}}\right) = [\mathrm{M}/\mathrm{H}]$ where $[M/H]$ is the star's total metal abundance (i.e. all ...
Gabriel's user avatar
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15 votes
0 answers
343 views

What is the limiting abundances of elements at the end of the stelliferous era?

Is there any reputable published source on expected elemental abundances at the end of the era of stellar fusion? I am here interested in the contents of galaxies; much of intergalactic gas will be ...
Anders Sandberg's user avatar
6 votes
0 answers
118 views

Need help understanding stellar spectroscopy data from ESO

The European Southern Observatory webpage has a web page that has tabular spectrogram data from A. J. Pickles, University of Hawaii. There are over 130 .dat files there. Each one represents a ...
Lakey's user avatar
  • 161
6 votes
1 answer
127 views

Metals and dust locked into planets

I wonder what is the contribution of metals and dust locked into planets, with respect to the amount in the interstellar medium (ISM). In other words, when we measure the metallicity and the dust mass ...
user avatar
9 votes
1 answer
1k views

Why do type Ia supernovas produce more iron than type II

My course book on astronomy states the following. Older stars seem have higher oxygen abundances than iron. Explanation is that back in the days when these older stars were being formed type II ...
Stijn D'hondt's user avatar
3 votes
1 answer
2k views

Relationship between metallicity and color? Should Pop. I stars be blue?

I have found in numerous places such as this website: http://burro.astr.cwru.edu/Academics/Astr222/Galaxy/Structure/metals.html or in "Introduction to Stellar Astrophysics" by B. Carroll, that state: ...
Guest's user avatar
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2 votes
2 answers
446 views

How could lithium burning take place in a quasi-star?

According to Begelman et al. (2008), one of the most distinguishing features of the hypothetical quasi-star is that it's supported by radiation pressure from the accretion disk of the black hole in ...
Sir Cumference's user avatar
9 votes
3 answers
853 views

Why does Gaia use only calcium NIR lines for stellar radial velocity measurements?

I was reading this overview article about the Gaia spacecraft and I saw the following statement: These spectra provide radial velocity information that are used to study the kinematic and dynamic ...
uhoh's user avatar
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0 votes
1 answer
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Metalicity and age of bulge stars vs halo [duplicate]

From what I understand of current models, the bulge of the galaxy formed first, and thus, would contain older population II like stars. Currently, however, the halo has a higher population of stars ...
NotSoSN's user avatar
  • 437
3 votes
1 answer
223 views

How can ionized emission line flux decrease as a function of increasing metallicity or abundance?

The chemical evolution of galaxies is an important way to learn about their formation and stellar/gaseous constituents. Many galaxies show narrow emission lines at optical wavelengths (3500-9000 ...
quantumflash's user avatar
5 votes
2 answers
1k views

Why do certain massive stars leave no remnants?

Mass and metallicity are the two main determinants for a star's fate. This is simple enough. What's more complicated is how exactly these determine the star's fate. For example, you can see in this ...
Sir Cumference's user avatar
4 votes
1 answer
143 views

Reason for a correlation between Hot Jupiters and higher metallicity in Kepler data

This question is from an amateur data analysis I did in May 2015 of data from Kepler.nasa.gov/Mission/discoveries. There were 80 Jupiter size planets in the Kepler "confirmed" planet table ...
Jack R. Woods's user avatar