Polaris
Polaris is a yellow star, much like the Sun in temperature, in the constellation Ursa Minor.
How far
430 light years
The light you see from Polaris tonight set off about 430 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 Everything we know about it is that much out of date.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
2,500 Suns
It gives out 2,500 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 1.97. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.
How hot
About 5,800 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.
PolarisThe Sun
In your sky now
Working it out…
Its names
- Its own name
- Polaris
- By constellation (Bayer)
- Alpha Ursae Minoris
- Hipparcos catalogue
- HIP 11767
- Henry Draper catalogue
- HD 8890
- Spectral type
- F7:Ib-IIv SB
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.