A Rosetta orbit is a complex type of

orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...

. In

astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

, a Rosetta orbit occurs when there is a

periastron An apsis (; ) is the farthest or nearest point in the orbit of a planetary-mass object, planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two maximum a ...

shift during each orbital cycle. A retrograde Newtonian shift can occur when the central mass is extended rather than a point gravitational source, resulting in a non-closed orbit. A prograde relativistic shift happens because of relativistic effects from a massive gravitational source. In barred spiral galaxies with a compact, lens-shaped bar (in contrast with a box-shaped bar), the morphology of the bar is supported by stars following rosette-shaped orbits that rotate with the bar. An object approaching a

black hole A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...

with an intermediate velocity (not slow enough to spiral into the hole and not fast enough to escape) enters a complex orbit pattern, bounded by a near and far distance to the hole and tracing an oscillating pattern known as a

hypotrochoid In geometry, a hypotrochoid is a roulette (curve), roulette traced by a point attached to a circle of radius rolling around the inside of a fixed circle of radius , where the point is a distance from the center of the interior circle. The par ...

. In 2020, scientists using observations made by the

European Southern Observatory The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental organization, intergovernmental research organisation made up of 16 m ...

Very Large Telescope The Very Large Telescope (VLT) is an astronomical facility operated since 1998 by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each equipped with ...

revealed for the first time that star S2 orbits in this pattern around

Sagittarius A* Sagittarius A*, abbreviated as Sgr A* ( ), is the supermassive black hole at the Galactic Center of the Milky Way. Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south o ...

. In

quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...

, the Rosetta orbit is a solution for spherically symmetric (except 1/r) potentials.

References

External links

Hubble telescope multimedia presentation on Black Holes
{{Orbits Orbits

See also

References

External links