Sirius
Sirius is a white star, hotter than the Sun, in the constellation Canis Major.
How far
8.6 light years
The light you see from Sirius tonight set off about 8.6 years ago. Everything we know about it is that much out of date.
How bright
23 Suns
It gives out 23 times as much visible light as the Sun. From the Earth it is the brightest star in the night sky. It is one of the brightest stars in the whole sky, easy to see even from a town.
Astronomers put its brightness in our sky at magnitude −1.44. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.
How hot
About 10,000 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.
SiriusThe Sun
In your sky now
Working it out…
Its names
- Its own name
- Sirius
- By constellation (Bayer)
- Alpha Canis Majoris
- Hipparcos catalogue
- HIP 32349
- Henry Draper catalogue
- HD 48915
- Spectral type
- A0m
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.
To read more: Colour and brightness, How stars live and die, Measuring distance.