Fomalhaut
Encyclopedia : F : FO : FOM : Fomalhaut
- This article is about the star. For the Demon Fomalhaut, see Demon Fomalhaut.
|- ! style="background-color: #FFFFC0;" colspan="2" | Details |- |style="vertical-align: baseline;" | Mass | M☉ |- |style="vertical-align: baseline;" | Radius | R☉ |- |style="vertical-align: baseline;" | Luminosity | L☉ |- |style="vertical-align: baseline;" | Temperature | K |- |style="vertical-align: baseline;" | Metallicity | |- |style="vertical-align: baseline;" | Rotation | |- |style="vertical-align: baseline;" | Age | })<()or(}})=()and(}})<())}}} years
|- ! style="background-color: #FFFFC0;" colspan="2" | Other designations |- | colspan="2" |
|} Fomalhaut (α PsA / α Piscis Austrini / Alpha Piscis Austrini) is the brightest star in the constellation Piscis Austrinus and one of the brightest stars in the nighttime sky. Its name means "mouth of the whale", from the Arabic فم الحوت fum al-ħūt. It is a class A star on the main sequence approximately 25 light-years (7.688 parsecs) from Earth.
Until about March 2000, Fomalhaut and Achernar were the two first magnitude stars furthest in angular distance from any other first magnitude star in the celestial sphere. Antares, in the constellation of Scorpius, is now the most isolated first magnitude star.
Fomalhaut is believed to be a young star, only 200 to 300 million years old, with a potential lifespan of only a billion years. The surface temperature of the star is around 8500 kelvin. Compared to the Sun, its mass is about 2.3, its luminosity is about 15, and its diameter is roughly 1.7.
It is surrounded by a disk of dust in a toroidal shape with a very sharp inner edge at a radial distance of 133 AU, inclined 24 degrees from edge-on. The dust is distributed in a belt about 25 AU wide; the geometric centre of the disk is offset by about 15 AU from Fomalhaut. The disk is sometimes referred to as "Fomalhaut's Kuiper belt".
Fomalhaut's disk is believed to be protoplanetary, and emits considerable infrared radiation. A planet, designated Fomalhaut b, has been inferred from analysis of the dust cloud in 1998.
Over history there have been a large number of variations on the star's name. It was first identified in pre-history and there is archaeological evidence that it was part of rituals in 2500s BCE in Persia where it would have been one of the Persians' four "royal stars". In the religion of Stregheria, Fomalhaut is a fallen angel and quarter guardian of the northern gate.
The much-fainter flare star TW Piscis Austrini is located within a light year of Fomalhaut and the two share a common proper motion through the sky. They are believed to be companion stars and may have had a common origin in a star cluster.
Fomalhaut in fiction and popular culture
- In fiction, Fomalhaut 3 is the homeworld of the Dorsai, a group featured in a large body of work initially created by the author Gordon R. Dickson.
- It is the location of a major space station, Alverez Station, in orbit about the planet Fomalhaut V (called America by the colonists) in the science fiction Roleplaying game by Tri Tac Games.
- Fomalhaut is one of the stars mentioned in the Cthulhu Mythos, the home of the god Cthuga.
- Tolkien fans, as well as New Scientist magazine and other mainstream publications, have noted the striking resemblance of the image of Fomalhaut's system shown on this page with the Eye of Sauron in the Lord of the Rings movies by Peter Jackson. However, the iris-like rays and concentric rings around the star in the picture from Hubble are artifacts from the coronagraph. Without these artifacts, the Fomalhaut system is only a single star surrounded by a dust ring and bears no known resemblance to any dark entities.
References
- Nature 435, 1067-1070 (23 June 2005) | doi: 10.1038/nature03601
External links
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