Extrasolar moon

Extrasolar moon

An extrasolar moon, or exomoon, is a term that refers to a smaller, natural (non-man-made) satellite that orbits an extrasolar planet or other extrasolar body larger than itself.

Definition of satellites around brown dwarfs

While traditional usage implies that moons orbit a planet, the discovery of planet-sized satellites around brown dwarfs blurs the distinction between planets and moons, due to the low mass of such failed stars. To resolve this confusion, the International Astronomical Union declared, "Objects with true masses below the limiting mass for thermonuclear fusion of deuterium," (currently calculated to be 13 Jupiter masses for objects of solar metallicity) "that orbit stars or stellar remnants, are planets" (no matter how they formed).

Theory and search

There are no known extrasolar moons, but their existence is theorized around many exoplanets. Future space telescopes such as Kepler, Darwin and New Worlds Mission will be able to search for moons orbiting extrasolar planets. Methods of doing this include imaging extrasolar planets directly and using the spectrograph to look for a wobble in their movement (just as wobbling in parent stars caused by planets); looking for the transit of the parent planet by its moon; or possibly imaging the moon directly.

Characteristics

Since no extrasolar moons have yet been discovered, their properties remain unknown. They are likely to vary, as do the properties of moons in our solar system. Some might be capable of supporting life.

Nomenclature

A system of nomenclature for extrasolar moons has not yet been decided by the International Astronomical Union, since no such moons have yet been discovered. Such a system would probablyFact|date=August 2008 use Roman numerals after the planet designations, with the numeral increasing according to order of discovery or of the moon's distance to its parent planets. For example, the moons discovered around 51 Pegasi b would be designated as "51 Pegasi b I", "51 Pegasi b II", and so on.Fact|date=August 2008

See also

* Extrasolar planet
* Natural satellite

External links

* [http://www.space.com/scienceastronomy/shadow_moons_021008-1.html Shadow Moons: The Unknown Sub-Worlds that Might Harbor Life]
* [http://www.space.com/scienceastronomy/planet_photo_040910.html Likely First Photo of Planet Beyond the Solar System]
* [http://www.dtm.ciw.edu/boss/definition.html Working Group on Extrasolar Planets - Defintion of a "Planet"] Position statement on the definition of a planet. (IAU)


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • Extrasolar planet — Planet Fomalhaut b (inset against Fomalhaut s interplanetary dust cloud) imaged by the Hubble Space Telescope s coronagraph (NASA photo) …   Wikipedia

  • Methods of detecting extrasolar planets — Any planet is an extremely faint light source compared to its parent star. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, only a …   Wikipedia

  • Discoveries of extrasolar planets — See also: List of extrasolar planet firsts Number of extrasolar planet discoveries per year as of 10 July 2011, with colors indicating method of detection …   Wikipedia

  • Aurelia and Blue Moon — are hypothetical examples of a planet and a moon on which extraterrestrial life could evolve. They are the outcome of a collaboration between television company Blue Wave Productions Ltd. and a group of American and British scientists who were… …   Wikipedia

  • Titan (moon) — Titan Titan in 2005 by Cassini spacecraft Discovery Discovered by Christiaan Huygens …   Wikipedia

  • Europa (moon) — Europa Europa s trailing hemisphere in approximate natural color. The prominent crater in the lower right is Pwyll and the darker regions are areas where Europa s primarily water ice surface has a higher mineral content. Imaged on September 7,… …   Wikipedia

  • Natural satellite habitability — Artist s impression of a hypothetical habitable moon of Upsilon Andromedae d Natural satellite habitability is the measure of a natural satellite s potential to sustain life. The study of natural satellite habitability is important to… …   Wikipedia

  • Terrestrial planet — The terrestrial planets Mercury, Venus, Earth, and Mars, and dwarf planet Ceres. Sizes to scale A terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks and/or …   Wikipedia

  • Rogue planet — This article is about a type of astronomical object. For other uses, see Rogue planet (disambiguation). Artist s conception of a Jupiter size rogue planet. A rogue planet (also known as an interstellar planet, or orphan planet) is a planetary… …   Wikipedia

  • Desert planet — This article is about the type of planet. For the Finnish electronic music band, see Desert Planet (band). A desert planet is a single biome planet on which the climate is mostly desert, with little or no natural precipitation. Desert planets are …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”