Meet a star / Pegasus

69 Pegasi

69 Pegasi is a white star, hotter than the Sun, in the constellation Pegasus.

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

How far

360 light years

The light you see from 69 Pegasi tonight set off about 360 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 Everything we know about it is that much out of date.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

43 Suns

It gives out 43 times as much visible light as the Sun. It can just be seen by eye from a really dark place.

Astronomers put its brightness in our sky at magnitude 5.99. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

Hotter than 11,000 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.

69 PegasiThe 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)
69 Pegasi
Hipparcos catalogue
HIP 115806
Henry Draper catalogue
HD 220933
Spectral type
A0MNp

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.