Meet a star / Orion

Mintaka

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

690 light years

The light you see from Mintaka tonight set off about 690 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 Everything we know about it is that much out of date.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

4,900 Suns

It gives out 4,900 times as much visible light as the Sun. It is one of the hundred brightest stars in the night sky. It is easy to see by eye on a clear night.

Astronomers put its brightness in our sky at magnitude 2.25. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

About 32,000 K

That is the temperature of its surface, worked out from its spectral type, O9.5II, with a standard table of how hot stars of each type are. It is a guide and not a measurement, and could be out by a tenth or so. Its colour alone would suggest only about 13,000 K. Dust lying between us and the star reddens its light, the way the air reddens the setting Sun, so for this star the type is the better guide. 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.

Mintaka, as it looks through the dustThe Sun

In your sky now

Working it out…

Its names

Its own name
Mintaka
By constellation (Bayer)
Delta Orionis
Hipparcos catalogue
HIP 25930
Henry Draper catalogue
HD 36486
Spectral type
O9.5II

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 read from the spectral type with the table of Pecaut and Mamajek (2013), and the words are written for this site.

To read more: Colour and brightness, How stars live and die, Measuring distance.