Ross 154
Ross 154 is a red star, among the coolest, in the constellation Sagittarius. It is in the long, steady part of its life, making helium from hydrogen in its core, as the Sun is.
How far
9.7 light years
The light you see from Ross 154 tonight set off about 9.7 years ago. Everything we know about it is that much out of date.
How bright
0.00 of a Sun
It gives out one 1,800th of the Sun's visible light. It is too faint to see without a telescope.
Astronomers put its brightness in our sky at magnitude 10.37. Smaller numbers are brighter, and the faintest stars the eye can see are about 6.
How hot
About 3,800 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.
Ross 154The Sun
Its names
- Its own name
- Ross 154
- Hipparcos catalogue
- HIP 92403
- Spectral type
- M3.5Ve
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.