Alpha Piscis Austrina
| Fomalhaut ( Piscis austrina) | |
 | |
| Observational data ( Epoch J2000.0 ) | |
|---|---|
| Right ascension | 22 h 57 m 39.05 s |
| Declination | -29 37 '20 " |
| Constellation | Southern Fish |
| Apparent magnitude | +1,17 |
| Features | |
| Spectral type | A3V |
| Index UB | 0,08 |
| Index BV | 0,09 |
| Index RI | ? |
| Variability | ? |
| Astrometry | |
| Radial velocity | 6.5 km / s |
| Proper motion | = 329.22 mas / a =- 164.22 mas / a |
| Parallax | 130.58 0.65 mas |
| Distance | 25 0.1 s. (7.66 0.04 pc ) |
| Absolute magnitude | +1,74 |
| Physical Characteristics | |
| Mass | 2.0 0.2 M |
| Radius | 1.84 R |
| Surface gravity (log g) | ? |
| Brightness | ~ 17.78 L |
| Temperature | 8760 100 K |
| Metallicity | ? |
| Rotation | ? |
| Age | 2-3 10 8a |
| Other designations | |
| Piscis austrina, 24 PsA ( Flamsteed ), GJ 881, HR 8728, CD -30 19370, HD 216956, GCTP 5565.00, LTT 9292, SAO 191524, FK5 867, HIP 113368 | |
Fomalhaut ( Piscis austrina) is the star the brightest of the constellation of the Southern Fish , and the 17th brightest star in the night sky. Its name comes from the Arabic al-fum which means "fish mouth" and is one of the four " royal stars "of the Persians , there are about 5000 years.
Summary |
Description
This is a star in the main sequence of spectral type A, located approximately 25 light years from our solar system.
It seems that a star Fomalhaut is relatively young, aged only 200 to 300 million years and whose life should not exceed one billion years. Its chemical composition is identical to that of the Sun.
Fomalhaut is surrounded by a dust disk-shaped torus whose inner edge is located about 133 AU from the star, more than three times the distance from the Sun to Pluto. This disc has a width of about 25 AU, a diameter of 20 billion km and its geometric center is offset by about 15 AU from Fomalhaut, it is sometimes called the Kuiper Belt of Fomalhaut.
Planetary system
Fomalhaut is the first star around which is detected through an optical photograph, an exoplanet. The photograph was published on 13 November 2008 and is taken by the Hubble Space Telescope. In a mass estimated to be three times that of Jupiter , the planet is called Fomalhaut b and is distant about ten times the distance between Saturn 's Sun .
References
- (en) Hubble captures first image of an exoplanet , Flashespace.com, 13 November 2008 . Posted November 13, 2008, accessed 14 November 2008
- (en) Planet Orbiting Hubble Observes Directly Fomalhaut on HubbleSite, 13 November 2008 . Posted November 13, 2008, accessed 14 November 2008
See also
Related articles
External Links
- (In) Sky and Telescope: Fomalhaut's Kuiper Belt
- (In) Fomalhaut , SolStation. Accessed September 8, 2007
- (In) ALF Psa , ARICNS. Accessed September 8, 2007
- (En) Alpha Piscis austrina the database Sinbad the Astronomical Data Centre Strasbourg
- (In) James B. Kaler, " Fomalhaut "on Stars
- (In) Bright Star Catalogue, " HR 8728 "on Alcyone
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