The Ghost of Jupiter, NGC 3242, is a planetary nebula in Hydra that looks like a pale blue-green disc about as wide in the sky as the planet Jupiter.
At a glance
| type | nebula |
|---|---|
| distance from the Sun | 4,320 light-years (1.32 kpc) |
| its light left it | 4,320 years ago |
| size in the piece | about 0.33 light-years acrossmodel |
Read off the piece’s own catalogue, the same values it draws with. Model marks a property of the piece’s galaxy model rather than a measurement.
About Ghost of Jupiter
NGC 3242 is a planetary nebula discovered by William Herschel. In a small telescope it is a bright bluish-green oval with an apparent size close to Jupiter’s, which is where its name comes from. The colour comes from glowing oxygen ions, energised by the hot white dwarf at the centre.
Deeper images show an inner shell, a brighter outer rim and a faint outer halo, each shed at a different stage of the star’s decline. Like the Saturn Nebula it has small, fast-moving knots of low-ionisation gas along its axis. Its brightness and clean structure make it a frequent target for testing models of how planetary nebulae form and expand.
What you see in the piece
In the piece it is a small cloud of glowing gas well above the plane of the disc; from the Sun it is a point.
Questions
Why is it called the Ghost of Jupiter?
Through a small telescope it appears as a pale disc roughly the size and shape Jupiter shows in the sky, but ghostly blue-green.
How far away is the Ghost of Jupiter?
The Ghost of Jupiter is 4,320 light-years (1.32 kpc) from the Sun.