Questions tagged [orbital-elements]
Questions about the parameters needed to specify the characteristics of an orbit.
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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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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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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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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 ...
user33354
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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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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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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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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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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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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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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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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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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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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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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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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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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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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 ...
user24627
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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 ...
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Orbital speed is (vector) sum of tangential and normal speed?
Orbital speed definition in wiki does not state clearly - it is just tangential speed component or square root of squares of normal and tangential speed (full speed vector).
When we say that moon ...
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Could someone please explain to me how I can extract velocity component values from Stellarium, for a given planet?
For a project that I am currently working on, I would like to know how one could extract velocity component values ($v_x$, $v_y$ and $v_z$) for a planet from the Stellarium software. The current ...
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Night-Day Cycles in S-Type Planetary Systems
I am a writer and space enthusiast. For a story I am currently writing I would like to have a planet which orbits a star which resembles the sun, which in turn orbits another star. In this situation ...
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Perihelion dates and parameters
I have to find the perihelion and aphelion data for the 20th century for Earth. I found this table http://www.astropixels.com/ephemeris/perap2001.html, but no such table for the past century.
I ...
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How Long Will Earth's Year be When Our Sun Goes Red?
We live in a planet that orbits 93 million miles from a G-type main-sequence star, or "yellow dwarf". That is far enough for a revolution of 365 days. Such is the case of Kepler's Third Law of ...
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In System KIC 9246715, How Far Does One Star Orbit the Other?
I was going to ask if it's physically possible for one red giant to orbit another, but fortunately, I have just found such a thing--a red giant binary system known only as KIC 9246715. In this ...
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Clearing the Neighbourhood: Definition of 'Orbital Region'?
I am trying to determine how wide a 'neighbourhood' a planet is expected to clear.
However, the Wikipedia article on the matter provides no clarity, simply stating that a planet is expected to clear ...
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periodic inclination change circumbinary planet
I am studying circumbinary planets and I made a python model to calculate certain properties of the orbits, and when I calculate the inclination I get a sine wave.
I do not see a way to predict the ...
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Are occultation observations used/useful for orbit determination?
The IAU Minor Planet Center lists $(486958)\space 2014 \space MU_{69}$ "Ultima Thule" as having an uncertainty parameter of 2, based on the observation arc of 851 days, from its discovery in 2014, to ...
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Relationship between Periapsis and apoapsis longitude
What is the relationship between Periapsis and Apoapsis longitude ? Are they 180° apart ? (ie) Periapsis + 180° = Apoapsis ?
Related question: if apoapsis is not known, what orbital elements are ...
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How was this interstellar fireball observed and its trajectory analyzed?
The short, interesting paper Discovery of a Meteor of Interstellar Origin describes a proposed discovery of a second interstellar object. This one hit the Earth, and was discovered not by telescope, ...
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How to draw an orbit from Orbital Elements using Transform3DGroup
I am trying to draw an orbit using the Transform3DGroup class in the C# .NET framework. I have orbital elements a, e, i, RAAN, ArgPer, trueAnom. The algorithm that spits these out for me also gives me ...
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Where can I find data on Mercury's orbit to fit a model to? [duplicate]
I have a project in which a Monte-Carlo method is used to find the optimal parameters for some model that is fit to a data set. I want to fit a model for the orbit of Mercury using this methods, but I ...
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How to calculate the argument of perihelion for exoplanets with incomplete orbital elements?
I'm trying to simulate the Kepler-444 exoplanetary system using data from this website. The problem is that there is no argument of periapsis parameter for the Kepler-444 system, so while I think I'm ...
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How to convert a function of keplerian elements to a function of equinoctial elements?
I need to convert the Keplerian orbital elements to the equinoctial elements and then use the converted elements"equinoctial" in the function "d" below. To do this, first, I converted the Keplerian ...
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Why is it impossible to estimate the inclination of an exoplanet with the Radial Velocity Method?
The formula of the radial velocity is:
$$v_i= V - K(\sin(f_i+\omega)\ + e\sin\omega),$$ with
$$K = \frac{m_p}{m_s+m_p}\frac{na\sin i}{\sqrt{1-e^2}}.$$
Being $V$the systematic velocity of the system,
...
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Calculate the orbital phase when plotting the Radial Velocity data of a transitting exoplanet
I'm not quite sure how I find the orbital phase ($\phi$) of a transitting exoplanet. For example, I have this RV data in this article:
First of all, I don't know how that phase or "cycles" is ...
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What is the range of the zenith angle between velocity and position vectors?
I'm coding on a space simulator and I want to draw a predictable orbit for a satellite. I have read about orbits on http://www.braeunig.us/space/ and under the section "Launch of a Space Vehicle" they ...
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Why is Neptune true anomaly decreasing?
So I've been having fun with trying to determine where the perihelia of different planets are (using JPL Horizons).
And by the time I got to Saturn, something weird started happening. I've noticed ...
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Explanation of Longitude of Periapsis [duplicate]
I'm looking for a mathematical justification of the longitude of periapsis as it makes no mathematical sense to me as a notion. By definition, it is the sum of the argument of periapsis and the ...
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Moonkeps PC program
Does anyone know where I could obtain a program called Moonkeps? It was an old MsDos based program that produced, I believe, the Keplerian elements for tracking the Moon and also the Sun. I wish to ...
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Problems with computing X,Y,Z positions of planets at a certain time in Unity3D (C#)
I'm trying to create a little program in Unity3D that positions the planets in 3D space at a given time. I've followed this document: http://stjarnhimlen.se/comp/ppcomp.html.
Using the data from ...
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Semi-major axis, vs aphelion, vs mean orbital distance?
The website Swinburne University of Technology (AU) gives the definition of semi-major axis as:
...half of the longest diameter of an ellipse.
This website give the definition of semi-major axis ...
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Tables of aphelion/perihelion dates for other planets?
It's relatively easy to find tables for Earth aphelion and perihelion dates and times, such as this one:
http://www.astropixels.com/ephemeris/perap2001.html
But what about the other planets in the ...
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Saturn's tropical year?
What is the value of Saturn's "tropical year" (as opposed to its "sidereal year").
I am seeing it listed as 10 days shorter (10,747 days) than the sidereal year (10,759.22 days).
How could this be ...
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Given sunrise, noon, sunset, longitude and latitude can I calculate the "hight" or "ascension" of the sun?
I'm trying to make a simple app for my own use to be able to check which of my favorit restaurants have outdoor seating sun and for how long etc.
Given the data in the title (sunrise, noon, sunset, ...
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