Meet a star / Crux

Tupã

Tupã is a yellow-white star, a little hotter than the Sun, in the constellation Crux. 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

120 light years

The light you see from Tupã tonight set off about 120 years ago. Everything we know about it is that much out of date.

How bright

2.0 Suns

It gives out 2.0 times as much visible light as the Sun. It is too faint to see without a telescope.

Astronomers put its brightness in our sky at magnitude 6.99. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

About 6,200 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.

TupãThe Sun

Its names

Its own name
Tupã
Hipparcos catalogue
HIP 60644
Henry Draper catalogue
HD 108147
Spectral type
F8/G0V

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.