Trojan asteroids,asteroids that revolve about the sun in the same orbit as a planet, occupying stable positions (known as Lagrangian points) either about 60° ahead of the planet in the orbit or about 60° behind it. Such asteroids were first discovered (1906) in Jupiter's orbit. In 1990, a similar asteroid, Eureka, was found in the orbit of Mars, and several others have since been discovered. Similar asteroids also have been found in Neptune's orbit since 2001, and a Trojan asteroid in earth's orbit was confirmed in 2011.
The Trojan asteroids represent one possible special solution to the famous three-body problem (see also celestial mechanics), with each group forming an equilateral triangle with the planet whose orbit they share and the sun. Some Trojan asteroids are composed of ice and dirt, rather than rock, making it possible that they are captured comets. The first Trojan asteroid discovered was Achilles, observed by the German astronomer Max Wolf; all of Jupiter's Trojan asteroids are named for heroes of the Trojan War.
"Trojan asteroids." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (October 24, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/trojan-asteroids
"Trojan asteroids." The Columbia Encyclopedia, 6th ed.. . Retrieved October 24, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/trojan-asteroids
Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:
Modern Language Association
The Chicago Manual of Style
American Psychological Association
- Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
- In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.