Questions tagged [globular-clusters]
Questions about large, dense, massive collections of stars orbiting galaxies, thought to have formed in the early universe.
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When should we use direct O(N^2) N-body simulation (instead of other methods)?
I've read a small tutorial on N-body simulation methods. What it says about direct N-body simulation is:
These codes are often used in star cluster dynamics or in other contexts where multiple stars ...
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Is there a good explanation for the existence of the C19 globular cluster with its very low metallicity?
The C19 globular cluster in the Milky Way has 1/2500 the metallicity of our sun. This means its stars were formed in the early universe. Is it likely to be the only cluster like this in our galaxy (...
user57831
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What is a Primordial binary?
I came across the term primordial binary in the article Stellar Collisions During Binary-Binary and Binary-Star Interactions by JM Fregeu:
"The realization during the 1990s that primordial ...
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python question-discrepancy between number of stars found
Ok, I get that this is a long question but it's ok if you don't know just thought I'd give this a try anyway. I get that it's a long shot. Basically I'm trying to replicate a methodology used in the ...
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Are there really confined Globular Clusters?
I am trying to find real physical examples of (self-gravitating) astrophysical systems that are appropriately confined and can thus be seen as in equilibrium. Modelling-wise, you can theoretically put ...
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Core radius of King's model
I've been learning about the King's model for globular clusters and have been taught that it assumes a core radius:
$$r_c = \sqrt \frac{9\sigma^2}{4\pi \rho_0 G} \ (1)$$
where $r_c$ is the core radius ...
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Average velocity of stars in globular cluster
This article explains how to calculate the mass of a globular cluster. The first equation is
\begin{equation}
v^{2}_{1D} = \sigma^{2}_{r}
\end{equation}
Can someone please elaborate why this is the ...
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Is it possible for a star cluster to be composed of main sequence stars?
From what I hear about globular clusters, they are primarily composed of very hot giant stars, which are not the most conducive for life as we know it.
Main sequence stars like our own, due to their ...
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Difference in HR diagram clusters
I was wondering what the difference in an HR-diagram would be between an open and globular cluster.
I've trying to compare both by looking up diagrams online, but can't find diagrams with same axes. I ...
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unstudied open clusters? [closed]
I want to know any open clusters which we don't know a lot about.
Open clusters of which we don't know about the:
chemical composition
ratio of no. of stars in front vs back tidal trail
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How to locate M13, Ring Nebula?
This is a bit last minute. I'm leaving shortly to go camping and expect to have dark skies. I watched NASA What's Up June 2020 which suggested checking out M13 (for which it gave pretty good ...
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How are globular clusters formed?
It is said globular clusters are usually very old and that they orbit around galaxies. But, I never read the reason why globular clusters are old, have that shape, and orbit around galaxies. What is ...
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Are the distribution of globular cluster systems in giant elliptical galaxies spherical?
I have been trying to find literature sources on the posted question in the title. The only source I found is from a 1991 review by William Harris which is provided here. In the review, the author ...
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Why do blue horizontal branch stars turn downwards on the HR diagram as opposed to red horizontal branch stars which remain fairly constant?
Horizontal branch stars (HB) burn helium at their cores. Red horizontal branch (RHB) stars experience an increase in temperature while their radii decrease so their luminosity remains somewhat ...
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Is this paper on globular cluster stability still up to date?
I'm looking to better understand the stability of globular clusters for an n-body dynamical simulation, specifically with respect to initial data conditions.
I know that the total potential energy ...
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Could we detect a globular cluster consisting entirely of black holes?
A paper recently came out in Nature simulating the evolution of the $\sim10^4M_{\odot}$ globular cluster Palomar 4 (Gieles et al. 2021, arXiv link). The authors argue that in ~1 billion years, a ...
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What is the mean distance of M53 Nucleus' stars ? (and other Globular Clusters) [duplicate]
Background: This Instagram post (from astronomypicturesdaily) tells that:
If our Sun were part of this star cluster, the night sky would glow like a jewel box of bright stars.
I opened this question ...
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How reliable is it to use globular cluster lumniosity function as a distance indicator?
I have seen many research suggesting that GCLF can be used as a secondary distance indicator for extragalactic objects. However, this method seems to be only reliable when the GCs in use come from say,...
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Do we have an accurate breakdown of star types in globular clusters?
I became interested in the breakdown of star types in globular clusters when trying to give a good answer in a Quora question. I had a difficult time finding an answer.
What I did find out was that ...
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What happens with a globular cluster when it passes through a galactic disc?
The orbits of globular clusters are crossing the disks of their galaxies, so they should sometimes pass through the disks. Are there any observed fluctuations in the clusters and in the disks ...
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What cluster of stars is this with a "dark donut" to one side?
In the 2011 Sixty Symbols video Spy Satellites (from Deep Sky Videos) after about 01:44 amateur astrophotographer Nik Szymanek shows an image of a cluster of stars ...
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Why aren't globular clusters disk shaped
I thought that solar systems and galaxies are disk-shaped because that is the most stable shape under gravitation. Globular clusters are very old, often times older than their host galaxies, so why ...
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How do we find the king model of a globular cluster?
We have data for a globular cluster M13. We have plotted the radius in pixels against the surface brightness in magnitudes per square arcsec.
We have to find the king model for this. We don't exactly ...
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Dataset for globular star cluster
Where can I find the
dataset(s) for a globular star cluster?
The datasets should have the coordinates, color index (for different wavelengths) , magnitude etc. of every star in the cluster.
I want ...
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What would our night sky look like if the solar system was 100 light years from the centre of the Milky Way
When we look at photo's of the centre of the Milky Way, it looks extremely bright due to the concentraion of star systems...
If our solar system was only 100 light years from the centre of the Galaxy,...
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Dataset containing list of known globular clusters
Does anybody know if there is an existing dataset that consists of all known star clusters, their name, and their apparent dimensions or similar? Is it possible to make a query to, or download all ...
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Is our Sun in a star cluster?
Sorry for the absolute beginner question here, but is our Sun a part of some globular cluster?
Is it something related to the Virgo supercluster?
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Help me identify a cluster [closed]
as I was browsing Nasa's Eyes few days ago, I saved a screenshot, but it seems text is blurrry, supher-485, first letter is S ends with er-485 from as I can read
it kinda looked like Cosmic Web, ...
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Jacobi vs tidal radius for star cluster
The tidal radius is defined in King (1962) as:
the value of r (the radius) at which f (the density profile) reaches zero...
This also referred by King as the "limiting radius" written as (Eq 3):
$...
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Globular Cluster diameter
I am doing a homework on globular clusters and could not find trustworthy data on the average diameter of a globular cluster. Most clusters I included had a diameter of 120-150 ly.
But is that the ...
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Do the heliospheres of stars at the center of globular clusters interact?
I read that the stars in the center of globular clusters are incredibly close to one another and that these stars can be spaced 100 to 1000 times closer than the stars near the sun. Because these ...
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Is it true that open clusters have $E > 0$ and globular clusters have $E < 0$?
I just need to confirm or refute something I'm believing since a very long time, maybe without real evidence.
Can we distinguish stellar clusters by their total mechanical energy ?
Is it true that ...
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Natural units of star clusters angular momentum and energy
I'm calculating the total angular momentum of a bunch of theoretical stars of a few solar masses, separated by a few light years, moving at velocities of about a few dozens of km / sec.
Mechanical ...
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How far apart are stars in Terzan 5 cluster?
I've just learned about the Terzan 5 globular cluster, which according to Wikipedia has one of the highest star densities in our Galaxy - $10^6\ M_\odot/\mathrm{pc}^3$.
Problem is, I've no idea how ...
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Why don't globular clusters flatten with a galactic disc?
Globular clusters lie in the galactic halo, outside of the disc. However, galaxies are more or less a collection of material and objects — why is it, then, that most stars form a plane due to the ...
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How many stars are there in a Globular Cluster of 10^5 solar masses?
I was wondering whether there is an easy way to approximate the number of stars in a Globular Cluster (GC) with 10^5 solar masses.
Can one, for instance just assume the GC is made of sun-like stars ...
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Distribution of Stars in Milky Way and globular cluster analogy
Just a quick (and hopefully simple) question on the distribution of stars in the Milky Way and in globular clusters. I was wondering why it IS NOT possible to describe the distributions of stars in ...
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Globular cluster star density as a function of distance from the center
Context: I want to simulate globular clusters in a simple way, just to display the positions of stars.
Assuming isotropy, what would be a reasonable model of the stellar number density as a function ...
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What is the difference between a dwarf spheroidal galaxy and a globular cluster?
This Wikipedia article states that Segue 1 is either a dwarf spheroidal galaxy or globular cluster associated with our own Milky Way. I am wondering what the difference is between dwarf spheroidal ...
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Is there a fundamental difference between a small galaxy, and a large star cluster?
For instance, If a large globular cluster were somehow ejected from its galaxy, and was observed by astronomers, would they call it a galaxy, or would there be characteristics of the star cluster that ...
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How would the night sky look from inside a globular cluster?
When the weather is clear, we can look at the stars. And we normally would see several thousands of them, they all being more than a $\textrm{pc}$ away from us.
Now, there are globular clusters, ...
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