Achird
Achird is a yellow star, much like the Sun in temperature, in the constellation Cassiopeia. It is in the long, steady part of its life, making helium from hydrogen in its core, as the Sun is.
How far
19 light years
The light you see from Achird tonight set off about 19 years ago. Everything we know about it is that much out of date.
How bright
About one Sun
It gives out about as much visible light as the Sun. It is easy to see by eye on a clear night.
Astronomers put its brightness in our sky at magnitude 3.46. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.
How hot
About 6,000 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.
AchirdThe Sun
In your sky now
Working it out…
Its names
- Its own name
- Achird
- By constellation (Bayer)
- Eta Cassiopeiae
- Hipparcos catalogue
- HIP 3821
- Henry Draper catalogue
- HD 4614
- Spectral type
- G0V 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.