Questions tagged [star-cluster]
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21
questions
1
vote
1answer
51 views
how to calculate the half-mass radius and tidal radius of a (simulated) globular cluster
I am exploring a dataset of a direct N-body simulation of a star cluster, such that all particles have the same mass and
G = M = −4E = 1
for the whole cluster. The data available is the positions ...
1
vote
1answer
34 views
What are the smallest star clusters affected by Galaxy Rotation Curve?
We all know that Milky Way exhibits Galaxy Rotation Curve which makes it rotate very differently that Newtonian mechanics would expect. But Milky Way is a pretty large galaxy, and the one we only see ...
6
votes
1answer
788 views
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 ...
8
votes
1answer
162 views
Is every star formed in an open star cluster?
As far as I understand, an open cluster is formed from a single molecular cloud, with each star in the cluster having roughly similar age and properties.
Our Sun is not part of any star cluster, but ...
6
votes
3answers
269 views
Whereabouts of the Pleiades
I assume they should be in the Milky Way galaxy. I have read about it a little but did not find information on where they are.
Which galaxy do the Pleiades belong to?
2
votes
1answer
210 views
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 ...
3
votes
2answers
353 views
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 ...
4
votes
1answer
134 views
Calculating obital velocity from radial velocity
I'm not really a physicist so I don't know if it's possible to get the real orbital velocity of a star from its radial velocity. I'm working on a paper for school and I want to get the mean velocity ...
2
votes
1answer
60 views
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, ...
6
votes
2answers
849 views
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):
$...
2
votes
0answers
153 views
Open cluster membership determination via parallaxes
I'm working in my final course project and I'm using the recently released GAIA DR2 data. I want to determine open clusters membership and I know this has mainly been done using proper motions and ...
1
vote
1answer
177 views
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 ...
1
vote
1answer
71 views
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 ...
1
vote
1answer
201 views
Understanding Scatter in Data collected for HR Plot
I was recently asked a question for a lab I am doing for an astronomy class where we collected data from the M44 cluster (through Google Sky) and used information about the Hyades cluster to estimate ...
-1
votes
1answer
227 views
Pleiades galactic coordinates
Is there a practical way to determine the galactic coordinates directly from the equatorial system?
Specifically, I can't find the $(l,b)$ for the Pleiades star cluster (M45) anywhere. I am trying ...
0
votes
1answer
461 views
Moving-Cluster method for determination of the distance of Hyades. A starter problem
I am currently following a class of observational astronomy lab. I will present a brief description of the method in first and then proceed to the question, so anyone is welcomed to read the entire ...
1
vote
1answer
224 views
What exactly is a stellar association?
What exactly is a "stellar association" in the strict kinematic sense?
8
votes
1answer
520 views
Astronomical databases for machine learning?
I was reading this question about open problems in astronomy. The bounty-receiving answer says that
I have just left the field where some colleagues are trying to develop some software to use ...
2
votes
2answers
194 views
Stars in star clusters in SMC and LMC
Is there any catalog or any paper published in any journal that lists the stars discovered under whichever star cluster of the Small Magellanic Cloud (SMC) they belong to? There is one for Large ...
8
votes
3answers
2k views
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 ...
5
votes
1answer
111 views
Who or what will the Arecibo message reach?
The Arecibo Message was aimed at the globular star cluster M13, but as far as I read, M13 will move out of the original position and thus not be able to receive it. So, who or what will be able to ...
