Questions tagged [orbital-elements]

Questions about the parameters needed to specify the characteristics of an orbit.

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5
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1answer
269 views

Could Planet X have a perihelion much closer than 300 AU and still be responsible for the gravitational interaction with 19 TNOs?

In August, Michael Brown and Konstantin Batigyn proposed new data concerning the hypothetical Planet X to explain the orbits of the 19 TNOs. They suggest a perihelion of 300 AU, but might Planet X be ...
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How would you calculate a Hohmann transfer going towards the sun? [migrated]

If you were going from a lower orbit to a higher orbit such as a Earth-Mars transfer, you would use the periapsis of the transfer orbit in the vis-viva equation to calculate the delta V. But if you ...
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415 views

Confused on how you are supposed to calculate eccentricity without apsides

I'm kinda confused on how to calculate either the apsides or the eccentricity without knowing one or the other. Let's say you have an object in orbit around another. If you know the current distance, ...
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Have we indirectly measured GW driven orbital decay in anything besides binary pulsars?

Binary systems decay for all sorts of reasons. I'm asking specifically about orbital decay due to gravitational wave emission. All of direct GW detections of binary systems have come with orbit ...
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How to translate from local laplace plane to ecliptic J2000 (or ICRF)

The NASA JPL websize gives mean orbital elements for e.g. Iapetus or Titan in relation to the local laplace plane. ...
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What's the formula for change in argument of periapsis over time due to J2 perturbations for a geocentric satellite?

I'm trying to propagate the orbit of the ISS, but it became very clear to me very quickly that the J2 perturbations were nothing to scoff at. A quick google search gave me the equation for the change ...
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Precision of orbital period of exoplanets vs solar system planets (Extrasolar Planets Encyclopedia)

I noticed that the Extrasolar Planets Encyclopedia lists the orbital period of L 98-59 b in days to 7 decimal places. Can astronomers really measure orbital period of exoplanets to greater precision ...
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What are the values of the Mean Anomalies of the planets in the Solar System?

I am trying to find a list of all the Mean Anomalies of the planets in the Solar System at the Epoch Jan 2000. I tried to Google it up but couldn't find any result. Can you please share the values or ...
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1answer
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Querying MPC data : P and Q vectors of any use to compute the eccentricity vector?

While querying the Minor Planet Center orbital data for asteroids, among the returned data, I noticed 6 variables corresponding to x,y and z components of two 3-D vectors namely P and Q. The ...
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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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Does Soter take into account Pluto's and Orcus' masses when determining Neptune's planetary discriminant µ?

Does Steven Soter's planetary discriminant µ1 for Neptune take into account the masses of Pluto, Orcus and other Kuiper belt objects crossing or coming very close to Neptune's orbit? If so, Neptune ...
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If the hypothesized planet behind the Kuiper belt existed, would it have a barycenter outside the Sun?

In 2016, an additional object rotating our Sun has been suggested. Assuming it has 5 Earth masses, would the planet or black hole proposed by Brown and Batigyn have a barycenter within the Sun or ...
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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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How likely are triple planet systems?

Is it likely to ever discover three planets of similar mass revolving around a common barycenter, or would such a system be too unstable? Such triple planet system would look like a triangle once in a ...
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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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What is the difference between the two terms named "Eccentricity" and "Ellipticity"?

I don't get the difference between the two terms named "Eccentricity" and "Ellipticity", especially, in astronomy. I understand eccentricity as a measure of the curvature of a ...
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1answer
163 views

Keplerian Elements

So, I've been doing endless research, and I've found a bit of information, all in different places, that is. Now, I'm getting really confused about it; I can't keep up with it all anymore, so, now, it'...
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Asteroids conjunction

I am currently writing a C++ program to show asteroids in 3D, and find close approaches or collisions. I got my orbital elements from JPL https://ssd.jpl.nasa.gov/sbdb_query.cgi. So far so good, with ...
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How to calculate center (not focus) of planetary orbit?

I'm developing a website showing the movement of Solar System planets according to the passage of time. I'm using this reference to calculate all the necessary orbital parameters. These are two images ...
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47 views

Visual binary star with circular apparent orbit

Does anyone know a good example of visual (or interferometric) binary star apparent orbit of which looks circular due to projection though in fact is markedly elliptical? I need that for teaching.
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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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1answer
144 views

Is Jupiter really shepherding the main belt, and Neptune the Kuiper belt?

By "dominating another object's orbit" my understanding is that the most massive body's gravity has so much influence that, when they come close, it makes the other body/bodies' orbits shift ...
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Based on discoveries of new TNOs since 2016, is planet Nine still necessary to explain the TNO's orbits?

It is almost five years since the announcement of the likelyhood of another planet that is responsible for clustering eTNO's orbits, very close perihelia of detached dwarf planets to the Sun, and high ...
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Problem with Tychonian model of geocentric universe?

Just like other proposed models of universe in history, Since Tycho's aren't being used, there MUST be any flaws in compare with widely agreed today understanding Is there any detailed reference ...
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994 views

"Periapsis" or "Periastron"?

I was taught from Bate Mueller and White, that the proper terms for the closest and furthest points and distances from a body in orbit around another unspecified body are "periapsis" and &...
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Are there any known low-inclination trans-Neptunian objects?

All the trans-Neptunian object's orbits I know are very inclined compared to those of the eight recognized planets, and Centaur's orbits are highly inclined as well. Are there any known Centaurs and/...
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What are "non-Keplerian" orbits? What are some familiar examples in our solar system, and can some still be closed?

This excellent answer to Forms of stellar orbits around the galactic center invokes the following concepts: non-Keplerian orbits closed orbits I have a fairly good idea what these mean and so might ...
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Forms of stellar orbits around the galactic center

Do all stars in orbit around Sagittarius A have approximately circular orbits or are there stars that orbit the Milky Way center very elliptically, like being in the Milky Way's outer rim at apoapsis ...
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The possibility of rapidly changing the Earths orbit via a passing astronomical object

I assume that the Earth could be “gently” (without colossal tidal or volcanic catastrophe) displaced by a passing extra solar star, brown dwarf or planet and end up perhaps 10% further away from the ...
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266 views

Easy interactive visualization of orbital elements

To get a grip on orbital elements, I'd like to play with a ready interactive visualization like in Universe Sandbox. E.g. drag the inclination slider and see immediately what happens to the satellite ...
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Orbital Mechanics: where can I find initial conditions for orientations and angular rates of planets in our solar system?

I am looking to write the equations of motion (EOMs) for a 6DOF analysis of our solar system. I want to integrate the equations forward in time, and need a complete set of initial conditions to do so....
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1answer
45 views

How do different formulas for calculating the mean anomaly of an elliptic orbit correlate?

I need to calculate the mean anomaly of an elliptic orbit at a specific point in time. I found two different formulas for $M(t)$ and I'd like to know how they correlate and if they result in different ...
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1answer
378 views

Cannot identify mistake in calculating orbital eccentricity vector; magnitude equals one instead of zero (with python code)

I have a gravitational nbody simulation, for which I would like to determine various orbital parameters. For each body, I have 3-D vectors (x,y,z -space) for position, velocity, and acceleration. I am ...
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2answers
184 views

Is the "mean orbit" centered on ellipse center or ellipse focus?

Mean longitude and mean anomaly of a body are calculated as the angle covered by the body along a fictious circular orbit, and this is ok. But where is this orbit centered? Five different sources say ...
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1answer
51 views

Apparent Centering Problem When Using the Perifocal System to Draw Orbital Ellipses [closed]

I am attempting to render orbital ellipses in software. Given a set of orbital elements, I am using the Perifocal system to determine a set of points along the curve of the ellipse. I am using the ...
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1answer
235 views

For what parameter does the abbreviation MA stand for?

In the sentence: "We added a Keplerian model with P = 120.713 days, m = 14.629M⊕, e = 0.0448, ω = 251.36°, and MA=216.88° plus Gaussian noise with rms=5.9696 ms-1." P is the orbital period, ...
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87 views

How can one determine the angle between the line of nodes and the major axis of the orbit of Mars?

Edit: What I really was looking for, was the difference in longitude on the orbit of Mars between its aphelion and the point where the north pole axis of Mars would point towards the Sun (northern ...
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1answer
227 views

Converting orbital elements from equatorial reference frame to ecliptic

I have a bunch of orbital elements (inclination, longitude of the ascending node, mean anomaly, argument of periapsis) that are all referenced from an equatorial reference frame. But the program I am ...
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Has the inclination of the orbital plane of Phobos and Deimos followed that of Mars' axial tilt?

Phobos and Deimos are very close to Mars' equatorial plane (the inclination of their orbits is roughly 1°). The axial tilt of Mars has changed a lot over time, and might have had a inclination of over ...
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1answer
86 views

How to calculate shape of orbit when projected onto the plane of the ecliptic

I'm trying to generate an 'overhead' view of the orbits of the moons of Neptune, similar to Figure 4 in this paper, using values given here. I initially tried using both the Argument of Periapsis, and ...
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1answer
106 views

How to project an arbitrary elliptical orbit onto the night sky plane?

An ellipse E is arbitrarily oriented in 3-D space with the origin at one of its foci. Use the standard elements provided in the figure. Assume the reference direction $\gamma$ or $\gamma'$ is the ...
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336 views

Keplerian Elements for Approximate Positions of the Major Planets

Simple question here. I am working on something that needs to compute an orbital path using Keplerian Elements. When doing some research I came across this JPL page: Click Here. Within that link is a ...
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1answer
191 views

Is the vernal equinox always in zenith somewhere on the equator?

I'm trying to visualize the satellit orbital parameter "right ascension of the ascending node" (RAAN). Measuring the angle from the vernal equinox to the point where the satellite's orbit crosses ...
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2answers
181 views

Is this a potential planetary setup for the Alpha Centauri System?

I originally posted this on the World Building SE, but I was suggested to post it here for a better answer. I am attempting to create a [semi]plausible star system in Alpha Centauri for a series. The ...
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Why isn't Eris considered a planet despite being the body of dominant mass?

The 2006 definition of a planet states that a planet is a celestial body that (a) is in orbit around the Sun (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it ...
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750 views

What is Charon's ascending node in reference to?

NASA's orbital elements given for Charon's orbit are given at https://ssd.jpl.nasa.gov/?sat_elem. The ascending node is defined as being "measured from the node of the reference plane on the ICRF ...
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1answer
86 views

Derivation of the orbital parameters of a exoplanet discovered by direct imaging

I wonder which orbital elements of a exoplanet can be found only applying direct imaging. I know that the angular separation combined with parallax can give us the semi-major axis, but what about the ...
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167 views

Kepler's equation and eccentric anomaly

From the wiki article about eccentric anomaly follows: $$\cos E = \frac{x}{a}$$ $$\sin E = \frac{y}{b}$$ where E - eccentric anomaly, a - semi-major axis, b - semi-minor axis, P = P(x,y) a point on ...
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136 views

Can Kepler's 3rd Law be applied in higher dimensions to describe orbits (quadric surfaces)?

Motivation for asking: The 2-D orbital path of a celestial body revolving around another celestial body due to the force of gravity can be described by a conic section; this is the curve formed by ...
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How to calculate the orbital velocity, the high-orbit (quasigeostationary) holding force and the shadow of the disk on Earth? [closed]

[] The following data are given: • The circular orbit of the disk D (quasigeostationary orbit) parallel to the geostationary orbit. • Located 4,505 km to the north of the equatorial plane, above ...