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In astronomy, a co-orbital configuration is a configuration of two or more astronomical objects (such as asteroids, moons, or planets) orbiting at the same, or very similar, distance from their primary; i.e., they are in a 1:1 mean-motion resonance. (or 1:-1 if orbiting in opposite directions). [1]
The basic elements of Ptolemaic astronomy, showing a planet on an epicycle (smaller dashed circle), a deferent (larger dashed circle), the eccentric (×) and an equant (•). In both Hipparchian and Ptolemaic systems, the planets are assumed to move in a small circle called an epicycle , which in turn moves along a larger circle called a ...
The orbit of every planet is an ellipse with the sun at a focus. More generally, the path of an object undergoing Keplerian motion may also follow a parabola or a hyperbola, which, along with ellipses, belong to a group of curves known as conic sections. Mathematically, the distance between a central body and an orbiting body can be expressed as:
Planet Taphao Thong was discovered in 1996 and was one of the first exoplanets to be discovered. [48] The planet was the first long-period extrasolar planet discovered. The other planets were discovered later. [49] Nu 2 Lupi: Lupus: 15 h 21 m 49.57 s: −48° 19′ 01.1″ 5.65: 47: G2V: 0.906: 5664: 10.36: 3: One of the oldest stars in the ...
The specific example discussed is of a satellite orbiting a planet, but the rules of thumb could also apply to other situations, such as orbits of small bodies around a star such as the Sun. Kepler's laws of planetary motion: Orbits are elliptical, with the heavier body at one focus of the ellipse. A special case of this is a circular orbit (a ...
The diagram shows a Hohmann transfer orbit to bring a spacecraft from a lower circular orbit into a higher one. It is an elliptic orbit that is tangential both to the lower circular orbit the spacecraft is to leave (cyan, labeled 1 on diagram) and the higher circular orbit that it is to reach (red, labeled 3 on diagram).
During a transit there are four "contacts", when the circumference of the small circle (small body disk) touches the circumference of the large circle (large body disk) at a single point. Historically, measuring the precise time of each point of contact was one of the most accurate ways to determine the positions of astronomical bodies.
Planet orbiting the Sun in a circular orbit (e=0.0) Planet orbiting the Sun in an orbit with e=0.5 Planet orbiting the Sun in an orbit with e=0.2 Planet orbiting the Sun in an orbit with e=0.8 The red ray rotates at a constant angular velocity and with the same orbital time period as the planet, =.