Fomalhaut / Alpha Piscis Austrini Star Facts (Type, Distance, Magnitude, Age, Mass, Colour, Location, Exoplanets and more)

Fomalhaut, also known as Alpha Piscis Austrini (Bayer) is a main sequence star located in the constellation of Piscis Austrinus, The Southern Fish. Fomalhaut is a major star and forms part of the constellation.

Based on the spectral type (A3V), Fomalhaut colour is blue - white, although not the hottest stars, they are considerably hotter than our own star which is white.

Fomalhaut temperature is in the range of between 7,500 and 10,000 Kelvin. Fomalhaut effective temperature is 8,760 Kelvin which is hotter than the Sun's effective temperature, which is 5,777 Kelvin. The uncertainty range for the effective temperature is between -8450 and +9070.

Fomalhaut is the brightest star in Piscis Austrinus and the 18th in the night sky based on the Hipparcos 2007 apparent magnitude. Based on a parallax of 129.81, Fomalhaut distance from Earth can be calculated at being 25.13 light years away or 7.69 parsecs.

Fomalhaut is a naked-eye star, so you don't need a telescope or binoculars when you look up on a clear night. The lower the magnitude, the easier it will be to see it.

Location

The location of the Fomalhaut in the night sky is determined by the right ascension (R.A.) and declination (Dec.). These are equivalent to the Longitude and Latitude on Earth. The Right Ascension (Longitude) is expressed in time (hh:mm:ss) and is how far the star is along Earth's celestial equator. If the R.A. is positive, then it's eastwards and vice versa.

The Declination (Latitude) is how far north or south the object is compared to the celestial equator and is expressed in degrees. If the value is positive, it is north of the celestial equator. For Fomalhaut, the location is 22h 57m 38.83 and -29° 37` 18.6 .

Based on the location of Piscis Austrinus, Fomalhaut can be located in the southern hemisphere of the celestial sky. The celestial hemisphere is equivalent to the hemispheres on Earth. Fomalhaut is south of the Ecliptic. The Ecliptic is the path that the Earth takes as it orbits the Sun. As the Earth is titled, we therefore have Celestial and Ecliptic hemispheres and they can be different for a star.

Physical Properties

Spectral Type

Fomalhaut spectral type of A3V which means its colour and type is blue - white main sequence star. There is no relationship between colour and size. For example, a red star can be large or small. Small stars are more energy efficient than larger stars and live longer.

Fomalhaut Luminosity

Luminosity is the amount of energy a star pumps out relative to the amount that our star, the Sun, gives out. Our star, the Sun's value is 1. Fomalhaut luminosity figure of 16.93 is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012. The star generates more energy than our star.

Fomalhaut Size (Radius)

Fomalhaut radius has been calculated as being 1.832 times bigger than the Sun. The Sun's radius is 695,800km, therefore, the Fomalhaut radius is an estimated 1,274,705.6.km. If you need the star's diameter, you just need to multiply the radius by 2.

Magnitude (Apparent / Absolute / Visible)

A number represents a star’s magnitude, whether apparent/visual or absolute. The smaller the number, the brighter the star is. The Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Fomalhaut apparent magnitude is 1.17, which is a measure of the star's brightness as seen from Earth. Apparent Magnitude is also known as Visual Magnitude.

If you use the 1997 parallax value, Fomalhaut' absolute magnitude is 1.74. If you use the 2007 parallax value, Fomalhaut' absolute magnitude is 1.74. Absolute Magnitude is the star's apparent magnitude from 10 parsecs or 32.6 light years. The magnitude assumes nothing is between the object and the viewer, such as dust clouds. To compare different stars' actual brightness, you would best use Absolute rather than Apparent Magnitude.

Fomalhaut is visible from Earth without needing binoculars or a telescope. The lower the Apparent Magnitude of a star or other object is, the easier it is to see in the night sky. An object with a magnitude greater than 6.5 cannot be seen without a telescope or other device.