Atria

Atria is an orange star, cooler than the Sun, in the constellation Triangulum Australe. It is a bright giant: a star that has left the steady part of its life and swollen up.

Fly to it in 3D Find it on the sky map

A drawing in the star's own colour, worked out from its measured colour index. It is not a photograph.

How far

390 light years

The light you see from Atria tonight set off about 390 years ago. Everything we know about it is that much out of date.

At this distance the figure could be out by a tenth or so.

How bright

2,200 Suns

It gives out 2,200 times as much visible light as the Sun. It is one of the hundred brightest stars in the night sky. It is easy to see by eye on a clear night.

Astronomers put its brightness in our sky at magnitude 1.91. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

About 3,900 K

That is the temperature of its surface, worked out from its colour, so it is a guide and not a measurement. It could be out by a few hundred degrees. The Sun's is 5,772 K. Hotter stars are bluer and cooler stars are redder, the same way a poker in a fire goes from red to white.

AtriaThe Sun

In your sky now

Working it out…

Its names

Its own name: Atria
By constellation (Bayer): Alpha Trianguli Australis
Hipparcos catalogue: HIP 82273
Henry Draper catalogue: HD 150798
Spectral type: K2IIb-IIIa

Where this comes from

Distance, brightness, colour and spectral type are from the HYG star database, version 4.4, by David Nash, shared under a Creative Commons Attribution-ShareAlike 4.0 licence. Its distances are those measured by the Hipparcos satellite. The temperature is worked out here from the colour with the formula of Ballesteros (2012), and the words are written for this site.