Meet a star / Auriga

63 Aurigae

63 Aurigae is an orange star, cooler than the Sun, in the constellation Auriga. 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

490 light years

The light you see from 63 Aurigae tonight set off about 490 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 Everything we know about it is that much out of date.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

210 Suns

It gives out 210 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 4.91. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

About 3,900 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.

63 AurigaeThe 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)
63 Aurigae
Hipparcos catalogue
HIP 34752
Henry Draper catalogue
HD 54716
Spectral type
K4II-III

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.