Questions tagged [astrophysics]
Questions involving the physics of the universe, especially the nature of astronomical objects, energy fields, and/or regions, rather than their positions or motions in space.
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Formula for "gravity assist"
I am familiar with the concept of "gravity assist" by which a space probe or other object, passing near a moving planet, can pick up some of the planet's orbital velocity.
I presume that ...
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Why is nuclear pasta the strongest part of a neutron star?
From my very rudimentary understanding of neutron stars taken from the abstract to "Elasticity of Nuclear Pasta", nuclear pasta is the strongest substance, hence the strongest part of a ...
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Why can't dark energy be considered a 5th fundamental force?
So I have recently been researching for multiple articles about fundamental forces, currently there are just 4 forces:
Gravity
Electromagnetism
Strong nuclear force
Weak nuclear force
So far there ...
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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 ...
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Elliptical galaxy classification
The elliptical galaxy (Hubble) classification goes from E0 to E7, with E0 being spherical and E7 being the most flattened. I understand that the angle at which the elliptical is viewed affects this ...
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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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Public data for calculating equilibrium temperature of exoplanets
I am a high school student beginning a simple independent project to calculate the equilibrium temperature of exoplanets. I'm curious to see how many exoplanets have a similar equilibrium temperature ...
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Concerning a binary system of stars/planets/black holes could one of them be ejected before eventually merging or colliding?
I was having a discussion with an undergraduate student of physics about binaries and their interactions with external celestial bodies (which could cause the ejection of one of the members in the ...
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is there any direct method to calculate gravitational wave frequency if the source mass is known?
Suppose we have neutron stars of 8 and 9 solar masses, they both merge and produce a GW. How does one find the frequency of the GW? Is there any specific formulae to compute it?
What I want to know is ...
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Is there such a thing as a map that shows the current (not observed) positions of celestial objects?
As I understand it, maps of the sky and three-dimensional maps of the universe all show the observed positions of celestial objects.
Are there any maps that show our best guess at their current ...
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Gravitational recoil with stars/planets...?
When two black holes are merging, the resulting merge can be ejected if one of the black holes had less mass than the other one, so the gravitational waves emitted by both of them is unbalanced, and ...
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How long would it take for a black hole of the mass of mercury to evaporate? [closed]
Mass of mercury, formula of time taken to evaporate by a black hole
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Why is final kinetic energy zero for escape energy calculations?
When the question is about the minimum speed to reach a certain point, we would usually use conservation of momentum, i.e. $\mathrm{E_k + E_p}$(initial) = $\mathrm{E_k(0) + E_p}$(final). I am curious ...
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Can rings last around planets indefinitely?
Apparently, Saturn is losing its rings (https://weather.com/en-IN/india/space/news/2023-05-04-saturn-is-losing-its-rings-webb-may-tell-us-how-long-they-have-left) However, is there any way or ...
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Do all orbits emit gravitational waves?
In principle, all orbits in the universe should progressively decay due to the emission of gravitational waves. However, does this always happen? Are there any kind of orbits that do not decay as they ...
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Typical astronomical and astrophysical problems in various programming languages
As a rule, work in the field of observational astronomy and astrophysics requires knowledge of such programming languages as: C/C++ and the principles of OOP, MPI, CUDA. Sometimes additional ...
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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 ...
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Why is the dark matter component of MOND important in central regions?
A lot of papers say that even the theory of MOND requires the existence of dark matter, particularly in the central regions. However this is a bit counterintuitive to me considering that rotation ...
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What are the primary astrophysical implications of a proposed mass of about 11 M⊙ for the SN 2023ixf progenitor?
The abstract of the arXiv preprint SN 2023ixf in Messier 101: A Variable Red Supergiant as the Progenitor Candidate to a Type II Supernova (itself recently "discovered" in the observatory) ...
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Is the Sun hotter today, in terms of absolute temperature (i.e., NOT total luminosity), than it was in the distant past?
I am constantly reading that the Sun is at least 20% 'hotter', in terms of total radiation/luminosity, than it was a few million years after its formation (i.e., after the Hayashi stage...)
But what ...
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What was FJM Stratton doing during Kamishari Expedition 1936, linked to Pearl Harbor intelligence?
In 1936, FJM Stratton, renowned Cambridge prof astrophysicist-radioastronomer, less-known but true, GC&CS-GCHQ intelligence officer and specialist FJM Stratton, led his Kamishari Expedition to ...
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How to plot the freeze out equation for massive particle species in Mathematica? [closed]
I want to recreate the figure . This comes from the Cosmological Boltzmann equation which can be modified as the number density equation as
$$\frac{dY}{dx}=-\frac{s(m)<{\sigma}|v|>[y^2-Y_{eq}^2]}...
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Seeking Guidance & Tips for Collaboration on a Cosmological Project Involving Potential Energy Variation Due to Cosmic Expansion
I'm a student with a deep interest in cosmology and astrophysics. I've embarked on a project and am seeking some guidance, insights, or even ways that I could look for possible collaboration on this ...
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Are liquids the rarest state of matter in the universe?
I was idly thinking what states of matter are common, which are rare overall. The commonest states of matter in the universe, by total mass, would be gases, solids (mostly as dust), and plasma (mostly ...
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What courses should one take for working towards Astronomy from an AI / Data Analysis perspective?
Note:- This is a suggestions seeking question
As a prospective student about to embark on pursuing the MEngg. in Applied AI program, I am eager to align my education with my passion for Astronomy. I ...
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Which coordinate system should one use for simulating a spacecraft trajectory to the moon? [closed]
Which coordinate system is most suited for this type of problem? ecliptic? equatorial?
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Trying to understand how to properly implement this equation to a healpix map
So i am working on reproducing a paper (Secrest, N. J., von Hausegger, S., Rameez, M., Mohayaee, R., Sarkar, S., & Colin, J. (2021). A test of the cosmological principle with quasars. The ...
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why does earth have speed?
I understand that Earth has a quite big speed such as it ends up around the orbit. The sun can't really attract it till the end due to Earth's speed and earth really can't escape due to gravity, hence,...
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Combining Systems Engineering and Cosmology/Astrophysics
in a nutshell, my undergrad was in Astrophysics, my master's is in Systems Engineering (SE), and I am currently completing my Ph.D. in SE focusing on deep learning applications towards engineering ...
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Why do cosmologists assume that inflation began shortly after the Big Bang, rather than at the exact start?
Somehow, I have never come across an explanation of why cosmologists claim that the alleged inflation of the very early universe occurred not at the Big Bang, but very shortly afterwards (~10^-36 to ...
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How does the gravitational wave strain from a rotating binary depend on the chirp mass, frequency and distance & what a short derivation looks like?
Our most familiar experience with wave propagation either from firsthand experience or in school comes from the phenomena of sound and light and radio electromagnetic propagation.
In air, we know that ...
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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 ...
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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 ...
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Would impacting plasma clouds destroy electronics on Earth or make them only temporarily inactive?
We read that solar flares have increased again recently. At the same time, it is always reported that the plasma clouds hitting the Earth would, under certain conditions, disable all electronics on ...
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Geocentric Planetary Configurations
An asteroid is orbiting the Sun in a circular orbit of radius 4AU. Calculate the ratio of its angular diameters at opposition and quadrature.
I have tried using the idea of elongation but it does not ...
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"And in some cases, a (free floating) planet (FFP) can form on its own outside of any solar system." Cool! But what are those cases?
The April 2, 2023 Inverse article 9 Years Ago, Astronomers Found Two Rogue Planets — But They Didn’t Realize It Until Now says:
Planets are typically part of a planetary system and are ...
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Formation of a non-Sol Oort cloud with high mass planets
Based on recent developments in astronomy, pertaining to a greater degree of measurement, the mass of the Oort cloud around Sol is apparently only about 1.5 times the mass of earth,in contrast to over ...
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Are more stars or more galaxies cataloged, currently, and how has the ratio evolved over time?
I recall that there are of order 100 billion stars in a galaxy and 100 billion galaxies in the (observable) universe, or something roughly like that.
Since we are IN a galaxy we have an opportunity to ...
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What do the symbols signify in Dr. Becky Smethurst's radiation pressure equation for black holes?
In her most recent video, "An ULTRAMASSIVE black hole has been discovered in a BRAND NEW way!", as well as a previous video, "How massive can black holes get?", Dr. Becky Smethurst ...
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Have we discovered a Galaxy lacking in Dark matter?
This question is relevant but it was speaking about a specific discovery reported by pieter van Dokkum, and the answer then mentioned it was disputed whether the paper's conclusion is even correct.
I ...
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What exactly IS a "Domain Wall"?
A Domain Wall is an "topological defect" and a 2-dimensional singularity. They are widely theorized to exist throughout the universe, but none have been detected yet. I'm having trouble ...
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Do brown dwarf 'stars' fuse simple hydrogen (p-p reaction) at all?
I sometimes read that only deuterium-deuterium fusion can occur in brown dwarfs... And maybe deuterium-proton fusion? To He-3?
In order to overcome Coulombic repulsion and, occasionally, fuse, protons ...
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Stellar structure equations - mass continuity
Out of the four stellar structure ODEs, I would like to understand why the mass continuity equation was named this way. It reads
$$ \frac{dm}{dr}=4\pi r^2\rho \tag{1} $$
and I understand what it means,...
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How can I get a list of the closest x stars and their distances from the Gaia ESA Archive using Python?
I've been trying to find this out for a while now, but I'm making zero progress. I really struggle to find good documentation for the query language, and even in the astroquery library I can't find ...
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Numerical Programming using ODEINT takes more than 17 minutes
I am trying to track the trajectories of a charged particles under the influence of Gravitational and Electromagnetic effect. Computing for time points, t0=0second -tf= (36002430)sec with stepsize 0....
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Motion equation of a space engine in low-earth orbit
My goal is to simulate the movement/motion of a space capsule from low-Earth orbit with initial conditions emulating an initial thrust. Here is the code, Is it right? I know that the next step is to ...
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Databases of measurements of galaxies
Where can I download databases on measurements of points in galaxies, for example, as in the attached pictures?
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Why are the largest stars, such as O-type or B-type, most likely to be in multi-star systems; while red dwarfs are least likely?
I was just reading about what percentage of stars in our galaxy and, perhaps, other galaxies are in binary systems (or trinary... etc.).
Researchers keep going back and forth about whether or not most ...
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If the Universe has a positive curvature and a closed spatial geometry, does it therefore have a finite volume and a geometric center?
Based on the recent Planck Legacy 2018 release confirming the presence of an enhanced lensing amplitude in the
cosmic microwave background (CMB) power spectra compared to that predicted by the ...
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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 ...
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