Meet a star / Apus

Zeta Apodis

Zeta Apodis is an orange star, cooler than the Sun, in the constellation Apus. It is a giant: a star that has used up the hydrogen in its core and swollen up.

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

How far

300 light years

The light you see from Zeta Apodis tonight set off about 300 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 Everything we know about it is that much out of date.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

90 Suns

It gives out 90 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 4.76. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

About 4,300 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.

Zeta ApodisThe Sun

In your sky now

Working it out…

Its names

It has no name of its own. Its name by constellation is a Greek letter and the constellation it is in, a way of naming begun by Johann Bayer in 1603.

By constellation (Bayer)
Zeta Apodis
Hipparcos catalogue
HIP 84969
Henry Draper catalogue
HD 156277
Spectral type
K1III

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.