Unanswered Questions
154 questions with no upvoted or accepted answers
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References to learn about algorithms/mathematics related to building planetarium / astronomy software?
I'm a beginner in astronomy with a background in engineering and mathematics. I'm interested in learning how to build astronomy software to model the position and movement of planets and stars, ...
- 181
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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
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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
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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
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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
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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
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It is possible to estimate an exoplanets' orbital period from just one transit?
Is one lightcurve containing a dip in brightness obtained from the transit method sufficient to obtain or estimate the orbital period of an exoplanet - such that one (first) observation could be used ...
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Probability of exoplanet transit
An exoplanet is in a circular orbit around its star.
The radius of the star is $r_{star}$
The radius of the exoplanet is $r_{planet}$
The radius of the orbit is $r_{orbit}$.
The orbital period of the ...
- 328
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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
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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 ...
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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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Calculate the uncertainty in measured flux density from an integrated intensity map
I have some ALMA data, in the form of a spectral cube, which I have integrated along the velocity axis to create an integrated intensity ('moment 0') map.
The integrated intensity map shows emission ...
- 1,386
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297
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How the heck does JPL actually do the numerical integration for their development ephemerides? (general questions)
After writing this answer to JPL Horizons - "highly accurate measurements of planetary positions" - how do they do it? which draws from Park, Folkner, Williams & Boggs 2021 The JPL ...
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What is the relationship between true anomaly and solar longitude?
So, my ultimate objective is to map solar longitude values onto a pseudo-Gregorian calendar. I thought this would be simple, but it has turned out to be anything but.
I have asked several questions on ...
- 141
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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 ...
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