The Helix Nebula star is the white dwarf at the centre of one of the nearest planetary nebulae, the cooling core of a star that shed its outer layers.
At a glance
| type | white dwarf |
|---|---|
| distance from the Sun | 649 light-years (199 pc) |
| its light left it | 649 years ago |
| luminosity | 76 × the Sun |
| radius | 0.027 × the Sun (18,800 km) |
| surface temperature | 104,000 K |
Read off the piece’s own catalogue, the same values it draws with.
About Helix Nebula star
The Helix Nebula, NGC 7293, in Aquarius is among the closest planetary nebulae to the Sun, so close that it spans a large patch of sky, though its light is spread too thin to see without help. At its centre sits the white dwarf left behind by the star that made it.
The white dwarf is still very hot and its ultraviolet light keeps the nebula glowing. Close to the star, images show a multitude of small dense knots with tails pointing away from it, clumps of gas being shaped by its radiation and wind.
Observations in infrared have found a dusty disc around the star, possibly debris from bodies that survived the star’s late stages.
What you see in the piece
Fly to the Helix Nebula and its central star is a small blue-white point; it is hot enough to be blue, too small to be bright.
Measured or modelled
The dusty disc around the central star is inferred from its infrared glow; whether it comes from colliding comets or other leftover bodies is an interpretation.
Questions
What is at the centre of the Helix Nebula?
A white dwarf, the exposed core of the star that shed the nebula. Its surface is about 104,000 K.
How far away is the Helix Nebula?
Its central star is 649 light-years (199 pc) from the Sun, one of the closest planetary nebulae.