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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In which town is the length of the day bigger on 23 of September?

I'm trying to solve this task: Moscow and Kazan are located on the same parallel. In which of them the length of the day is bigger on 23 of September? In Kazan the sun will rise earlier, because it'...
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Finding the new true anomaly after performing a maneuver [migrated]

Given a standard set of orbital elements (angular momentum, semi-major axis, eccentricity, inclination, longitude of the ascending node, argument of periapsis, and true anomaly), and a global time ...
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Virgin Galactic's and Blue Origin's Space Flights - are these just Extended Skydiving in an Enclosure? [closed]

Sorry for three questions in the three paragraphs below, but they all are around the same curiosity that I have. In both of Virgin Galactic and Blue Origin's space flights happening in July 2021, it ...
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Confusion when calculating the length of the day

I'm trying to solve this task: Tula and Moscow are located on the same meridian. In which city length of the day is bigger on 22 of June? 22 of December? I was thinking like that: we need to ...
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relation between angular velocity of planet and orbital velocity [closed]

Can it be shown that angular velocity of a planet = (orbital velocity/h+Radius): $$\frac{v_{c,1}}{h + R_{⊕}} = \omega_e $$
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Mars is getting closer to Earth through its elliptical orbit becoming more eccentric. Do Earth and Mars keep getting closer? [closed]

A NASA Mars article says: Mars' orbit is more elliptical than Earth's, so the difference between perihelion and aphelion is greater. Over the past centuries, Mars' orbit has been getting more and ...
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Virial theorem for a binary system

I am trying to derive the virial theorem but for two stars orbiting each other. I know the derivation for the general virial theorem with i particles but I am wondering if there is a quicker or more ...
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Degrees of freedom in restricted circular coplanar three body problem

How many degrees of freedom does a mechanical system consisting of three bodies, the Sun, Jupiter and an asteroid, have in the restricted circular coplanar problem of the three bodies? I know that if ...
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Can we learn anything from the chaotic movement of Hydra and Nix?

The NASA Visualization Explorer Moons In Chaos says Hydra and Nix, two of the moons of Pluto, show chaotic movement due to the shifting gravitational field. How long a day lasts and where the sun ...
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Orbital resonance 2:1

I considered the motion of an asteroid around the sun, in a $2:1$ orbital resonance with Jupiter. Following the study of this resonance, it was observed that the angle between the major axis of the ...
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Can Stellar Spaghetti ever escape?

Spaghettification is the deformation of a body into long, thin strips due to tidal forces as the body passes through a powerful gravitational field. Image from wikipedia: Stellar spaghetti has been ...
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When an object revolves around an oblate planet, in near-circular orbit, does the oblateness ALWAYS make it moves FASTER?

tl;dr: The orbital period for a Keplerian orbit of a small body around a massive one with standard gravitational parameter $\mu=GM$ and semi-major axis $a$ is given by $$T = 2\pi\sqrt{\frac{a^3}{\mu}}....
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Trajectory: What would happen if the sun disappeared one day?

So, let's just assume, to no aspect explainable to humans, the sun just magically popped out of existence on January 1st next year (2022), that'll never happen, this is just a scenario to explain my ...
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Non-keplerian orbit features

For the first Kepler's law the orbit of a planet is an ellipse, with the Sun in one of the foci, but I've read that in the case of an homogeneous sphere distribution, orbits can be elliptic, but the ...
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Orbital Angular Momentum of a Binary Star System

Let's say you have a binary star system, consider the orbital motion of that binary star consisting of two solar-like stars separated by 20 stellar radii. How would one calculate the angular momentum ...
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Nodal Precession of Planets

It is obvious that the longitude of ascending node ($ \Omega $) of a planet gradually changes with time. For example, the VSOP planetary theory accounts for this. In Astronomical Algorithms (Meeus ...
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Where can I find a list of retrograde Milky Way stars?

I read in papers that the Milky Way contains some retrograde stars (retrograde to the Milky Way rotation). Does anybody know where I can find a list of them, possibly including data on their distance ...
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What is the period of the 'cycle' of Earth's ecliptic variation, relative to the 'invariable plane'? 70,000 or 100,000 years?

The plane of Earth's path around the Sun, the ecliptic, is different from the average of the solar system's as a whole (the invariable plane) by about 1.57°.... Our path around the Sun, though, goes ...
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Orbital path projections onto a 2D plane

In ProfRob's excellent answer to Is S2 still the fastest known star in the galaxy?, he posted a figure of the orbital paths of stars passing close to the supermassive black hole near the center of the ...
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Could photons orbit a black hole if fired at the correct angle?

My experience with Kerbal Space Program gives me the impression that it's impossible to transfer from a stable orbit of one body to the stable orbit of another without deceleration. But is this true ...
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Is S2 still the fastest known star in the galaxy?

Wikipedia's entry for the star S2 says that it has the fastest known ballistic orbit, reaching speeds exceeding 5,000 km/s (11,000,000 mph, or ​1⁄60 the speed of light) and acceleration of about 1.5 ...
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What is the longest natural bound orbit chain observed?

Define a bound orbit chain as a list of successively less massive bodies, each in a bound orbit with the bodies preceding it in the list. Then an example of a bound orbit chain would be: <Sun, ...
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Why do the asteroids orbit the Sun in roughly the same plane as the planets?

The asteroid belt between Mars and Jupiter is an extremely active environment (on an astronomical time scale) where collisions between 10km radius bodies occur every $10^7$ years, according to ...
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Moons within a Gas Giant

Assuming a gas giant is primarily gaseous past our visibility, is it possible that a moon traveling at a sufficient velocity would be able to exist within the atmosphere, or would terminal velocity ...
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How can I find the width of an orbit knowing some values?

I need to find the width/x-radius of an orbit, which is ellipse shaped, knowing variables like the orbit's length(perihelion + aphelion in this case) and the eccentricity. I am not sure if this is ...
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Could our Sun be the product of an ancient stellar collision?

The canonical model for the formation of the Solar System involves the gravitational collapse of a nebula into (perhaps) several stars across several light years. Is it possible that two or more of ...
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Computing the rate of orbital decay

We know that the estimated time until a binary system merges is given by: $$\dfrac{5c^5r^4}{256G^3(m_1m_2)(m_1+m_2)}$$ But what is the formula to determine rate of decay, in some sort of distance unit,...
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What is the thickness of the Solar System disk?

What is the thickness in AU of the all planets' orbital plane height combined in the Solar System? Excluding Pluto. Looking for h
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Prograde to retrograde orbital path

Is there a planet or planetary moon flyby path that could send a solar prograde orbiting asteroid into a retrograde solar orbit?
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Could an orphan/rogue planet have a moon?

Is there some reason why an orphan or rogue planet wouldn't have a moon? Let's say it started out in a normal system and then just got flung out by an unstable orbit.
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What exactly was the Moon's “Evection Resonance”?

Ward et. al define the evection resonance of the Moon with the Earth and Sun as: occurring when the lunar perigee precession period equals one year. Does this simply mean that the angle formed by ...
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How to choose initial state vectors for a resonant orbit numerical simulation?

How do higher numbers affect orbital resonance? is a really interesting question, and I thought I would try to do a simple numerical simulation of various resonance ratios to see if some are ...
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Was Newton the first to mention the orbital barycenter?

A barycenter is the common center of mass of an orbiting system. Here is a illustrative gif from wikipedia: The first mention of something like a barycenter that I could find is in a translation of ...
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How to track orbit of an exoplanet?

I was wondering if there is an established method to keep track of the orbit of an exoplanet assuming we know a - the semi-major axis of the orbit, e - the eccentricity of the orbit, and i - the ...
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Galactic orbits and distance between stars

In the context of whether or not nearby stars were created from the same nebula, this answer states: imagine two stars with very similar orbits, one with a period of 200 million years and the other ...
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Do moons of rocky oblate planets migrate to low inclination over time? If so, does the time it takes depend on the Moon's size?

Discussions elsewhere suggest that this happens and that smaller moons would tend to low inclination with respect to the planet's equator faster than larger ones. For example, Mars' small moons are ...
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Do the orbits of planets change? Where is the data for this?

Everything in the space is moving all the time. Do the orbit of major Solar Systems planets, Mercury to Saturn change? Just like Moon's orbit around Earth changes. How often, how small or big is the ...
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What is the antonym of “closest approach”?

The distance from Earth to Mars, during their closest approach, is about 55 million kilometers. At their furthest apart, that distance would be about 401 million kilometers. Distance at closest ...
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Classical Mechanics : Interaction Sun Radiation Pressure - Gravitation

I have a theoretical problem that merges the effects of a gravitational field and the Sun radiation pressure. The problem goes as follows: A spacecraft orbits the Sun in absence of any other body ...
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Sun's and planets' inclination to the Invariable plane

What are the inclinations of all major Solar system planets (Mercury to Pluto) to the invariable plane? Looking for accurate data calculated on them. Also, What is the inclination of the Sun to the ...
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Moon's and nodes' inclination to the Invariable plane

Moon is inclined to the ecliptic 5.14 degrees. Earth's inclination to the invariable plane is 1.57869 degrees. What is the Moon's, and node's inclination to the invariable plane? Since the Moon has an ...
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What calculations show that Comet Shoemaker-Levy 9 orbited Jupiter for several decades before its spectacular impact? (Chodas, Sekanina & Yeomans)

This answer to A moon in eccentric orbit dipping below Roche limit includes the following about Comet Shoemaker–Levy 9 Here is a nice figure of its last passes: I looked up "fragment A" in ...
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Calculating the Angular Momentum of a planet

I want to calculate the Angular Momentum of any planet at any point on the orbit around the Sun. Example: I want to calculate the Angular Momentum of Pluto today, on Jan 27, 2021 00:00:00 Hrs Where ...
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Did Aliens make Oumuamua?

Dr. Avi Loeb, the distinguished astrophysicist and chair of Harvard's Astronomy Program, just published a book called Extraterrestrial: The First Sign of Intelligent Life Beyond Earth. In the book, Dr....
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Semi major axis of an hyperbolic orbit

The semi major axis (a) is not immediately visible with an hyperbolic trajectory but can be constructed as it is the distance from periapsis to the point where the two asymptotes cross. Usually, by ...
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Are there any stars that orbit perpendicular to the Milky Way's galactic plane?

Most stars orbit in the Milky Way's galactic disc. But is it possible for one to orbit perpendicular to it? Here on Earth since we're inside the galactic plane we can't get a good view of what the ...
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Why is dark matter required?

I read somewhere that the galaxy is spinning too fast (in places). Therefore, there must be dark matter. What are the equations that explain how fast the galaxy should be moving, and how are they ...
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Are there any moons of minor planets that orbit at high inclination to the plane of rotation of the parent body?

It occurred to me that one of the ringed asteroids or minor planets may answer this question about the alignment of planetary rings. However, it appears that the rings of Chariklo, Haumea and Chiron (...
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Kepler's Law, focal points - Heliocentric or Barycentric?

It is known that all the mass in the Solar system moves around the Barycenter. For the two focal points in Kepler's law; is the first focal point $F_1$ a Heliocenter? Or is it actually a Barycenter? ...
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When will Callisto be in orbital resonance with the rest of Jupiter's big moons?

The four Gallilean moons of Jupiter (from innermost) are Io, Europa, Ganymede, and Callisto. Io, Europa, and Ganymede are in a 1:2:4 orbital resonance. Callisto's orbital period is 16.689 days, which ...

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