Sadachbia
Sadachbia is a white star, hotter than the Sun, in the constellation Aquarius. It is in the long, steady part of its life, making helium from hydrogen in its core, as the Sun is.
How far
160 light years
The light you see from Sadachbia tonight set off about 160 years ago. Everything we know about it is that much out of date.
How bright
63 Suns
It gives out 63 times as much visible light as the Sun. It can be seen by eye away from bright lights.
Astronomers put its brightness in our sky at magnitude 3.86. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.
How hot
Hotter than 10,000 K
That is the temperature of its surface, worked out from its colour, so it is a guide and not a measurement. For stars as blue as this one, colour is a poor thermometer: most of their light is ultraviolet, which the eye and this sum do not see, and the true figure can be far higher. 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.
SadachbiaThe Sun
In your sky now
Working it out…
Its names
- Its own name
- Sadachbia
- By constellation (Bayer)
- Gamma Aquarii
- Hipparcos catalogue
- HIP 110395
- Henry Draper catalogue
- HD 212061
- Spectral type
- A0V
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.