Meet a star / Vulpecula

Anser

Anser is a red star, among the coolest, in the constellation Vulpecula.

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 Anser 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 Everything we know about it is that much out of date.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

120 Suns

It gives out 120 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 4.44. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

About 3,800 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.

AnserThe Sun

In your sky now

Working it out…

Its names

Its own name
Anser
By constellation (Bayer)
Alpha Vulpeculae
Hipparcos catalogue
HIP 95771
Henry Draper catalogue
HD 183439
Spectral type
Composite: two stars measured as one

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.