The term extrasolar moon refers to a smaller, natural (non-man-made) satellite that orbits an extrasolar planet or other extrasolar body larger than itself. This article is about artificial satellites For natural satellites also known as moons see Natural satellite. An extrasolar planet, or exoplanet, is a Planet beyond the Solar System, orbiting around other Stars As of September 2008 312
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Definition of satellites around brown dwarfs
While traditional definitions imply that all moons must 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. A natural satellite or moon is a Celestial body that Orbits a Planet or smaller body which is called the primary. A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is Brown dwarfs are sub- stellar objects with a mass below that necessary to maintain Hydrogen -burning Nuclear fusion reactions in their cores as do stars Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth 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). The term true mass is synonymous with the term Mass, but is used in Astronomy to differentiate the measured mass of a planet from the lower limit of mass usually obtained In Physics and Nuclear chemistry, nuclear fusion is the process by which multiple- like charged atomic nuclei join together to form a heavier nucleus Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth In Astronomy and Physical cosmology, the metallicity of an object is the proportion of its matter made up of Chemical elements other than Hydrogen
Theory and search
There are no known extrasolar moons, but their existence is theorized around many exoplanets. An extrasolar planet, or exoplanet, is a Planet beyond the Solar System, orbiting around other Stars As of September 2008 312 Future space telescopes such as Kepler, Darwin and New Worlds Mission will be able to search for moons orbiting extrasolar planets. A space observatory is any instrument in Outer space which is used for observation of distant planets galaxies and other outer space objects The Kepler Mission is a Space Photometer being developed by NASA. The Darwin Mission is a proposed European Space Agency (ESA program designed to directly detect Earth -like planets orbiting nearby stars, and search for The New Worlds Mission is a project funded by NASA Institute for Advanced Concepts (NIAC headed by Dr 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. A spectrometer is an Optical instrument used to measure properties of Light over a specific portion of the Electromagnetic spectrum, typically used The term transit or astronomical transit has three meanings in astronomy A transit is the astronomical event that occurs when one
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. Life is a state that distinguishes Organisms from non-living objects such as non-life and dead organisms being manifested by growth through Metabolism
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 probably 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. Roman numerals are a Numeral system originating in ancient Rome, adapted from Etruscan numerals.
See also
External links
- Shadow Moons: The Unknown Sub-Worlds that Might Harbor Life
- Likely First Photo of Planet Beyond the Solar System
- Working Group on Extrasolar Planets - Defintion of a "Planet" Position statement on the definition of a planet. An extrasolar planet, or exoplanet, is a Planet beyond the Solar System, orbiting around other Stars As of September 2008 312 A natural satellite or moon is a Celestial body that Orbits a Planet or smaller body which is called the primary. (IAU)
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