Questions tagged [orbital-mechanics]
The application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft.
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Do the Galilean moons' orbits around the Sun have loops (i.e. have concave parts)? And if so, how can their orbits be graphed?
The shape of the Moon's orbit around the Sun has been discussed to death, and the answer is that the Moon's orbit has no concave "loops" whatsoever.
I am relatively sure that the determinant ...
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Would a planet's tidal forces really push away a moon out of its Hill Sphere?
If a moon orbits in the same direction as its planet's rotation (i.e. a prograde orbit), and its orbital period is longer than its planet's rotational period, then tidal forces would cause the moon to ...
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Appropriate NEO databases for preliminary orbit determination simulations
I am a high school student that is currently writing an extended essay in physics. In my essay I compare the accuracy of Gauss method and double-r iteration method for determining the preliminary ...
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Equation for calculating boolean answer to "is this Earth satellite in eclipse"
I have found plenty of math for determining duration of satellite eclipse, but I am having trouble finding an equation that produces a simple boolean answer to the question "Is this Earth ...
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Should you include aberration effects during low Earth orbit observations?
I am working on calibration of some observations of low Earth orbit satellites and I am wondering should I include aberration effects? My logic is that diurnal aberration would have neglegible ...
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Corkscrew-like stable two-body system
I recently created a celestial body simulation in python for one of my classes. While playing around with different values I obtained a weird two-body stable system.. For context, these bodies are ...
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Hierarchy of gravitational interactions of astronomical objects: from single to large-scale structures
Hierarchical structure is clearly visible in the Universe. The "observable universe" includes almost empty voids, between which lie large cosmic filaments. The filaments consist of galactic ...
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Three Body Problem using Python
I need help with an assignment. I'm doing a little project for a subject on my university and as the title says, its to find a solution to the three body problem restricted to a circular motion.
The ...
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How do the orbits of star systems V871 Centauri (septuple), Gamma Cassiopeiae (octuple), and QZ Carinae (nonuple) work?
Several years ago, I asked the question on here, "How do the orbits of Nu Scorpii and AR Cassiopeiae work?" At the time, these two stellar systems were the most populated (I don't know the ...
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Apsidal precession
I found this article about calculating apsidal precession:
https://farside.ph.utexas.edu/teaching/336k/Newton/node115.html
I tried to calculate rate of apsidal precession from this equation, but I had ...
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Orbit of the moon so that there are no eclipses
Theoretically speaking, what orbit should the earth's moon must take so that there are never any eclipses - solar or lunar? Is it mathematically possible to construct such an orbit?
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How to convert TEME (or ITRF) to horizontal
I have TEME coordinates from sgp4 propagation. I can convert those (in python) to ITRF given date and time of observation. How to convert coordinates from one of those two frames to horizontal azimuth ...
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Under which conditions could a planet's massive moon's orbit get closer to the planet?
The recent question How do we know the Moon was much closer than it is now? has piqued my interest. The answers are numerous and clear. But I started to wonder. The question includes the following ...
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How to turn find velocity dispersion from radial velocity
In the above given picture Vi is the velocity of the i-th galaxy in the cluster while Vm is the mean velocity of a galaxy in the cluster. and V i,r is the radial velocity of the i-th galaxy and V m,r ...
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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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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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Eccentricity of TLE orbit from velocity and radius in TEME
I was reading this question: Calculation of Eccentricity of orbit from velocity and radius and tried to use the proposed equation to reconstruct the ecco field of TLE by it's R,V vectors. The formula ...
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Will all satellites get inevitably tidally locked to their planet?
Are there cases or conditions in which an object orbiting another one (e.g. a satellite and its planet) does not get tidally locked to it?
For example, in this question, it is mentioned that a large ...
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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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What is the shape of orbit assuming gravity does not depend on distance?
We know that the orbit of the earth is elliptical considering the force of gravity is inversely proportional to the square of the distance. But assume that, gravity does not depend on distance. ...
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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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What is the difference between SPICE kernels and JPL Development Ephemerides? Is a DE just a bunch of kernels on a string?
My imposter syndrome is acting up again after I posted several comments under:
What is the mathematics needed for understanding DE440 and translating it into xyz coordinates?
Now I feel like I don't ...
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What is the mathematics needed for understanding DE440 and translating it into xyz coordinates?
I would like to write my own code to process NASA's DE440/DE441 ephemerides, but I do not know the mathematics needed to do this.
I understand packages such as pyephem have implemented variations of ...
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Are dust-dust collisions necessary to explain Kordylewski clouds at Earth-Moon L4/5? Aren't the cross-sections, number density timescales too small?
The recent question Can dark matter accumulate at Lagrange points? mentions Kordylewski clouds and that article begins:
Kordylewski clouds are large concentrations of dust that exist at the L4 and L5 ...
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Code for Gauss's method orbit determination
I'm trying to calculate the state vectors of the ISS using Gauss's method with three sets of values (right ascension, declination and sidereal time). I'm following the method described in "...
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Why did the path of J002E3 pass through almost the same point four times?
In 2002–2003, an object called J002E3 passed close to the earth in a chaotic orbit.
According to NASA CNEOS (Center for Near Earth Object Studies) the orbit looked like this:
(This is a screenshot of ...
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What moons have cleared their orbits?
The Wikipedia article Clearing the Neighborhood lists three numeric parameters that can be calculated for bodies orbiting the Sun as a way to indicate orbital dominance: Stern and Levinson's $\Lambda$,...
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Are there such circumbinary planet configurations that two suns move towards each other by the sky?
Is it possible that suns move towards each other (not necessarily in opposite directions)? Such a configuration would cause interesting dusk and midday light cycles, in my opinion.
Basically the ...
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Is it possible to have satellites (natural or not) orbit the same celestial object in different directions ? (clockwise, counterclockwise)
Is it possible to have satellites (natural or not) orbit the same celestial object in different directions, or is the orbital direction dependent on the celestial object's spin?
Also, is the direction ...
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largest balanced mass objects in Earth's L4 & L5 Lagrange points?
What is the largest single-object mass that would allow two objects of equal mass to have a stable orbit, one each, in Earth's L4 and L5 Lagrange points?
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Eyeball planets experiencing "catastrophic" flips
This Youtube video by Anton Petrov shows research1 claiming that tidally-locked planets orbiting the same star in tight orbits may interfere with one another and one planet may cause the other to &...
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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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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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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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Eccentricity with a law of gravity different from the classical one
How can I calculate the eccentricity of the orbit of a planet (with mass equal to that of the Earth) around a star (with mass equal to that of the Sun) assuming that the force of gravity is given by ...
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Moon's equation of the centre discrepancy
According to the Wikipedia Lunar Theory article, the first term of the Moon's equation of the centre is
$$22,639^{\prime\prime}\sin l,$$where $l$ is the Moon's mean anomaly. According to the Wikipedia ...
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What is the most stable orbit around the moon?
Let’s say I wanted to build a space habitat in orbit around the moon. Better still, let’s say I want to build a ring of habitats occupying the same orbital path, encircling Luna, to oversee the mining/...
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Different techniques for calculation of celestial bodies dynamics with different time-scales
Differential equations describing the dynamics of celestial bodies (rotation, nutation, precession and other effects) can be solved numerically, which makes it possible to study their general non-...
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What is the mean inclination for randomly oriented orbits? How to derive it?
I know the answer is $60^o$. But I can't seem to be able to derive the result.
Specifically, how to define the probability density function (PDF) for this problem? Once I have that it should be ...
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What's the meaning of "hard supermassive black hole binary"?
In this paper, the authors state in the Introduction that
A hard SMBHB [SuperMassive Black Hole Binary] can eject surrounding stars to transfer their orbital energy and angular momentum, which may be ...
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Is there an orbit around the earth that experiences a total solar eclipse by the Moon at least every month?
Is there a way to design an earth orbit so that it passes through the Moon's umbra with greater frequency than total solar eclipses occur on earth's surface?
What is the maximum frequency of eclipses ...
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From a given latitude on Earth, how to calculate the number of days in a year when the moon is lit on the bottom?
From a given latitude on Earth, is it possible to calculate the number of days in a year when there is a wet moon , that is when the moon is lit on the bottom?
If, for example, I want to do the ...
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What is meant by " elliptical galaxies stabilize due to the chaotic motion of stars"?
I read that elliptical galaxies stabilize due to the chaotic motion of stars. As I understand that means that the stellar motions are more nearly random in direction. So they perform independent ...
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How to call the fear of no gravity? [closed]
In opposite to barophobia I can't google out a fear of the case, when a man is taken out of the ship and he must go through the spaceship's docks and he can't get the direction of gravity - in the ...
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Radial velocity
Is there a way to calculate the radial velocity without wavelength? I can only find two formulas so far. One of them needs wavelengths and the other one needs the velocity of the star, but I have none ...
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How do star orbits, density wave theory and dark matter distribution work together?
I got confused while trying to combine these 3 concepts. Would love to hear some detailed explanation.
Density wave theory states that spiral arms are formed by tilted elliptic orbits. Bertrand's ...
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Radial velocity of host stars and exoplanets
I am new to astronomy/astrophysics.
(1) In the CATALOG OF NEARBY EXOPLANETS, I came across the following terms.
Please see Table 2 of the above paper. 12th column lists $v \sin(i)$ - It is the radial ...
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Orbital Stability of a Double Planet System
I recently found an article claiming a double planet system needs to be at least .5 AU from its parent star to be stable for billions of years. It was specifically talking about two same-mass bodies, ...
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Does the Inverse Square Law mean that the apparent diameter of an object of same mass has the same gravitational effect?
Someone else asked about various planets located at the orbital range of the Moon. It made me wonder if an object with the same density as the Moon, at a distance which would present the same angular ...
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How can I determine a planet's orbital size if it is moving around an oscillating star?
I'd like to know how to calculate the size of the planet's orbit, given that it is the only one orbiting around a star, and that this star is oscillating with an amplitud of 0.026'' in 25 year periods....
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