Meet a star / Orion

56 Orionis

56 Orionis is an orange star, cooler than the Sun, in the constellation Orion. It is a bright giant: a star that has left the steady part of its life 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

1,300 light years

The light you see from 56 Orionis tonight set off about 1,300 years ago. Everything we know about it is that much out of date.

Distances this great are hard to measure, and this one could be out by a fifth or more.

How bright

1,600 Suns

It gives out 1,600 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 4,000 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.

56 OrionisThe Sun

In your sky now

Working it out…

Its names

It has no name of its own. Its name by constellation is a number and the constellation it is in, from the catalogue of John Flamsteed, the first Astronomer Royal.

By constellation (Flamsteed)
56 Orionis
Hipparcos catalogue
HIP 27750
Henry Draper catalogue
HD 39400
Spectral type
K2IIvar

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.