Questions tagged [metallicity]
Questions regarding the fraction of metal to non-metal elements, with metals being elements other than hydrogen and helium.
42
questions
4
votes
0
answers
142
views
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 ...
1
vote
1
answer
79
views
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....
1
vote
0
answers
54
views
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/...
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 ...
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-...
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.
22
votes
2
answers
5k
views
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 ...
6
votes
1
answer
201
views
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 ...
3
votes
3
answers
168
views
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?
...
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 ...
0
votes
1
answer
420
views
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 ...
4
votes
0
answers
54
views
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 ...
9
votes
1
answer
820
views
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 ...
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 ...
1
vote
1
answer
176
views
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 ...
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 ...
1
vote
0
answers
98
views
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 ...
5
votes
1
answer
829
views
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 ...
13
votes
1
answer
2k
views
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 ...
3
votes
0
answers
48
views
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-...
1
vote
0
answers
45
views
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 ...
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 ...
6
votes
0
answers
45
views
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 ...
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 ...
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 ...
6
votes
1
answer
310
views
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 ...
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 ...
3
votes
1
answer
1k
views
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 ...
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 ...
2
votes
0
answers
67
views
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 >...
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 ...
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 ...
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 ...
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 ...
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 ...
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:
...
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 ...
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 ...
0
votes
1
answer
125
views
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 ...
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 ...
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 ...
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 ...