Atria / Alpha Trianguli Australis Star Facts (Type, Distance, Magnitude, Age, Colour, Location and more)

Atria, also known as Alpha Trianguli Australis (Bayer) is a giant star located in the constellation of Triangulum Australe, The Southern Triangle. Atria is a major star and forms part of the constellation.

Based on the spectral type (K2IIb-IIIa), Atria colour is orange to red, these are stars that are cooler than our own star.

Atria temperature is in the range of between 3,700 and 5,200 Kelvin. Based on the spectral type (K2IIb-IIIa) as we don't have the exact temperature', we can deduce that the surface temperature of Atria is in the order of 3,500 and 5,000K based on the notes from Harvard University. To put this in context, the temperature of our Sun is about 5,778 Kelvin as said by Google.

Atria is the brightest star in Triangulum Australe and the 42nd in the night sky based on the Hipparcos 2007 apparent magnitude. Based on a parallax of 8.35, Atria distance from Earth can be calculated at being 390.61 light years away or 127.39 parsecs.

Atria 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 Atria 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 Atria, the location is 16h 48m 39.87 and -69° 01` 39.5 .

Based on the location of Triangulum Australe, Atria can be located in the southern hemisphere of the celestial sky. The celestial hemisphere is equivalent to the hemispheres on Earth. Atria 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

Atria spectral type of K2IIb-IIIa which means its colour and type is orange to red giant 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.

Atria 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. Atria luminosity figure of 5,309.95 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.

Iron Abundance

Atria Iron Abundance is -0.06 with an error value of 9.99 Fe/H, with the Sun having a value of 1 to put it into context. The value comes from the Hipparcos Extended Catalog.

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.

Atria apparent magnitude is 1.91, 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, Atria' absolute magnitude is -3.62. If you use the 2007 parallax value, Atria' absolute magnitude is -3.48. 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.

Atria 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.