Unanswered Questions
113 questions with no upvoted or accepted answers
2
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What could these LMC objects in this color-color diagram be?
I have performed a color-color and colour-magnitude plot of various sources detected in an LMC image (JWST NIRCAM F200W, F150W and F115W filters). I then also queried SIMBAD to collect relevant ...
- 21
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34
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Could rogue planets with cold nucleus have winds or water currents/waves due to the planet's rotation?
Are there any types of wind or waves caused and produced only and exclusively by a planet's rotation? Not influenced by the planet's rotation, but produced solely by it?
In the case of waves, are ...
- 1,017
2
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61
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Is there an equation that can give position of a satellite around a parent body as a function of time?
I’ve been looking into this lately, and most sources I have used solve this problem numerically. I was thus wondering if there is a proper equation to solve for position without numerical, especially ...
- 201
2
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101
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Conversion of 1D plot in 3D plot gives different physics
I am to track the path of a particle due to Lorentz force of the planet magnetic field, assuming there is no gravitational force on it.
The equation of motion due to Lorentz force in rotating ...
- 145
2
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answers
250
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Abundance of an element Xi in mass fraction from its abundance by number
How can I calculate the expression of the abundance of a given element Xi in mass fraction from its abundance by number Ni/NH, where log(NH) = 12 is the abundance by number of hydrogen?
I've tried the ...
- 4,800
2
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29
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Equation describing Energy Transport due to Radiation in the interiors of stars
I am considering a very elementary stellar structure and I'm required to derive an equation to describe the energy transport due to radiation. The answer I am supposed to obtain is:
$$\frac{dT}{dr}= -\...
- 779
2
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42
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"First gamma-ray eclipses from ‘spider’ star systems" - but have other types of gamma-ray eclipses been observed?
The January 28, 2023 NASA News item NASA’s Fermi Detects First Gamma-Ray Eclipses From ‘Spider’ Star Systems begins:
Scientists have discovered the first gamma-ray eclipses from a special type of ...
- 15k
2
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46
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How do I calculate the flux density of a substellar object?
I am currently trying to generate photometric passband colors for brown dwarfs and planets generated through MESA (Modules for Experiments in Stellar Astrophysics). I believe I understand the ...
- 61
2
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56
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The necessary conditions for driving winds with dust (Dust-driven Wind)
So lately I've read Intro to stellar winds (particularly chapter 7 Dust-driven winds) by Lamers & cassinelli, I forget how many times I've read this but I still don't really understand. So in the ...
- 123
2
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32
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Where can I find definitions of minimum detectable flux sensitivity and signal to noise ratio?
I am struggling to find references that give precise definitions to these concepts. Even in PhD theses on the subject of gamma-ray astrophysics, for example, students do not define it precisely or ...
- 2,169
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Is it possible to infer information about the structure of the universe beyond the observable one?
Is it possible to infer information about the structure of the universe beyond the observable one, by observing its effects on the parts we can see? Can for example gravity from sources we cannot see ...
- 2,364
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342
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Cosmology context plotting : Covariance matrix - Script to plot Omega_m vs Omega_Lambda diagram in Python
I have covariance matrices and Markov chains coming from the SCP (Supernova Cosmology Project) and I would like to plot all these data
in the particular diagram Omega_Lambda vs Omega_m or w vs Omega_m....
CommunityBot
- 1
2
votes
0
answers
54
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What is the sun's maximum influence on a magnetic object?
How much magnetic repulsion could the sun's magnetic field produce on an magnetic object? Consider the object is ideal: It could be flat, to create more resistance, balanced, to stay on the opposing ...
- 6,300
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44
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Looking for analytical expression of Cosmic Variance - Poisson distribution?
I have an expression of Matter Angular power spectrum which can be computed numerically by a simple rectangular integration method (see below). I make appear in this expression the spectroscopic ...
CommunityBot
- 1
2
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0
answers
140
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Poisson noise for a squared contrast of density - expression of variance equal to $1/n^2$
I manage to compute the Poisson noise of a density field like this :
If I take $N$ the density of galaxies and compute the Shot noise with a Poisson distribution, I get :
$\langle N^2\rangle - \...
CommunityBot
- 1