The Ring Nebula star is the exposed core of a dying Sun-like star at the centre of the Ring Nebula, a small, intensely hot white dwarf that makes the ring glow.
At a glance
| type | white dwarf |
|---|---|
| distance from the Sun | 2,580 light-years (790 pc) |
| its light left it | 2,580 years ago |
| luminosity | 200 × the Sun |
| radius | 0.03 × the Sun (20,900 km) |
| surface temperature | 125,000 K |
Read off the piece’s own catalogue, the same values it draws with.
About Ring Nebula star
The Ring Nebula, M57, is a planetary nebula, the outer layers of a star like the Sun cast off at the end of its life. What remains at the centre is the bare core: a white dwarf, not much larger than the Earth, still extremely hot from the star’s former furnace.
Its ultraviolet light ionises the gas around it, and the gas glows in colours set by its elements: oxygen near the centre, hydrogen and nitrogen further out. The star itself is faint in visible light, because most of its output is ultraviolet.
With no fuel left, the white dwarf will cool and fade, and the nebula will thin and disperse, while the star lives on as a dimming ember.
What you see in the piece
Fly to the Ring Nebula and the central star is a tiny blue-white point inside the ring; it is faint because it is so small, though fiercely hot.
Questions
What is at the centre of the Ring Nebula?
A white dwarf, the hot, exposed core of the star that shed the nebula. Its surface is about 125,000 K.
Why is the Ring Nebula star hard to see?
It is tiny, only 0.03 × the Sun (20,900 km), and most of its light is ultraviolet, so it is faint in visible light.