Meet a star / Hercules

100 Herculis (HIP 88818)

100 Herculis (HIP 88818) is a white star, hotter than the Sun, in the constellation Hercules. 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

160 light years

The light you see from 100 Herculis (HIP 88818) tonight set off about 160 years ago. Everything we know about it is that much out of date.

How bright

10 Suns

It gives out 10 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 5.83. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

About 8,500 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.

100 Herculis (HIP 88818)The Sun

In your sky now

Working it out…

Its names

It has no name of its own. Its name by constellation is a number and the constellation it is in, from the catalogue of John Flamsteed, the first Astronomer Royal.

By constellation (Flamsteed)
100 Herculis
Hipparcos catalogue
HIP 88818
Henry Draper catalogue
HD 166045
Spectral type
A3V

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.