Meet a star / Pisces

Revati

Revati is a white star, hotter than the Sun, in the constellation Pisces. It is a subgiant: a star just beginning to leave the long, steady part of its life.

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

How far

170 light years

The light you see from Revati tonight set off about 170 years ago. Everything we know about it is that much out of date.

How bright

20 Suns

It gives out 20 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 5.21. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.

How hot

About 7,800 K

That is the temperature of its surface, worked out from its spectral type, A7IV, 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. For stars as hot as this, colour is a poor thermometer, because most of their light is ultraviolet, so 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.

RevatiThe Sun

In your sky now

Working it out…

Its names

Its own name
Revati
By constellation (Bayer)
Zeta Piscium
Hipparcos catalogue
HIP 5737
Henry Draper catalogue
HD 7344
Spectral type
A7IV

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.