Meet a star / Orion

Meissa

Meissa is a blue star, among the hottest there are, in the constellation Orion.

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

How far

1,100 light years

The light you see from Meissa tonight set off about 1,100 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 Everything we know about it is that much out of date.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

4,300 Suns

It gives out 4,300 times as much visible light as the Sun. It is easy to see by eye on a clear night.

Astronomers put its brightness in our sky at magnitude 3.39. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

Hotter than 12,000 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.

MeissaThe Sun

In your sky now

Working it out…

Its names

Its own name
Meissa
By constellation (Bayer)
Lambda Orionis
Hipparcos catalogue
HIP 26207
Henry Draper catalogue
HD 36861
Spectral type
O

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.