Meet a star / Pictor

Mu Pictoris

Mu Pictoris is a blue-white star, far hotter than the Sun, in the constellation Pictor. It is in the long, steady part of its life, making helium from hydrogen in its core, as the Sun is.

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

How far

760 light years

The light you see from Mu Pictoris tonight set off about 760 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 Everything we know about it is that much out of date.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

250 Suns

It gives out 250 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 5.69. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

Hotter than 10,000 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.

Mu PictorisThe 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)
Mu Pictoris
Hipparcos catalogue
HIP 31137
Henry Draper catalogue
HD 46860
Spectral type
B9V

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.