Interstellar object
An interstellar object (Latin inter stellas 'between the stars') is an astronomical object that is located in interstellar space and is not gravitationally bound to a star. The term can also be applied to objects that are in an interstellar orbit but temporarily passing near a star, such as B. certain asteroids and comets (including exocomets ). These objects are characterized by a hyperbolic trajectory , i.e. H. select a path with an eccentricity greater than 1. By the end of 2019, two objects were identified in the solar system that clearly have their origin in interstellar space: 1I / ʻOumuamua and 2I / Borisov .
observation
Due to the great distances, an interstellar object can usually only be recognized when it passes the solar system , where it follows a hyperbolic orbit in this area . In contrast, gravitationally bound objects follow elliptical orbits around the sun, like most asteroids, comets and objects in the Oort cloud .
Examples
So far, two interstellar objects have been detected in our solar system. The first interstellar object discovered is 1IʻOumuamua , formerly called C / 2017 U1 and A / 2017 U1. The track has a numerical eccentricity of about 1.20. In 2019 the comet 2I / Borisov was discovered, the hyperbolic orbit of which has an eccentricity of about 3.4. amounts. 1I'Oumuamua was only discovered after its perihelion and was therefore only observable for a few weeks. 2I / Borisov was discovered on his way to the sun and is expected to be observable until around October 2020. Since it is also larger and more active than Oumuamua, it is hoped that the observations will provide more scientific information.
Interstellar objects are likely planetesimals that were created as a by-product of star and planet formation and later left their home star . There are a number of processes that can result in planetesimals being catapulted out of the home system. It is possible for objects orbiting a star to be ejected through interaction with a third massive body, thus becoming interstellar objects. Such a process was initiated in the early 1980s when C / 1980 E1 , initially gravitationally tied to the Sun, passed near Jupiter and was accelerated enough to reach the speed of escape from the solar system. This changed its orbit from elliptical to hyperbolic, making it the most eccentric known object of the time, with an eccentricity of 1.057. It is heading for interstellar space.
Recent research suggests that the asteroid (514107) Kaʻepaokaʻawela may be a former interstellar object captured about 4.5 billion years ago, as demonstrated by its co-orbital motion with Jupiter and its retrograde orbit around the Sun. A team of researchers led by Coryn Bailer-Jones was able to trace the trajectory back up to 6.3 million years.
Artificial interstellar objects
The space probes Pioneer 10 , Pioneer 11 , Voyager 1 and Voyager 2 are also in hyperbolic orbits and never return to our solar system. The probes reached the third cosmic speed ( ) by swing-by maneuvers on Jupiter and Saturn. New Horizons was launched directly into a hyperbolic orbit and also carried out a swing-by maneuver on Jupiter in order to shorten the flight time to the primary mission target Pluto .
Individual evidence
- ↑ Researchers find possible home of comet "Oumuamua". Retrieved February 22, 2019 .
- ↑ UH astronomy team helps confirm 2nd potential interstellar object. University of Hawaiʻi at Mānoa , September 12, 2019, accessed September 18, 2019 .
- ↑ The 'Oumuamua ISSI Team: The natural history of' Oumuamua . In: Nature Astronomy . tape 3 , no. 7 , July 2019, ISSN 2397-3366 , p. 594–602 , doi : 10.1038 / s41550-019-0816-x ( nature.com [accessed October 2, 2019]).
- ^ Solar System Dynamics & Planetary Group: General Description C / 1980 E1 Bowel. Retrieved September 16, 2019 .
- ↑ Tilmann Althaus: An interstellar asteroid in the solar system. In: Spectrum of Science. May 21, 2018. Retrieved May 23, 2018 .