A planetary nebula represents one of the final stages
in the life of a star like our own Sun
Near the end of its life, before it consumes all of its remaining fuel
a star expels its outer layers
These are then excited by the radiation of the star
and begin to glow brightly, showing intricate and fascinating structures
that scientists are still trying to fully understand
Hubblecast episode 61: a tour of NGC 5189
Presented by Dr J, aka Dr Joe Liske
Hi and welcome to the Hubblecast
In previous episodes, we’ve looked at a lot of Hubble’s images of planetary nebulae
and we’ve talked about how they tell us about the ultimate fate of our own Sun
In this episode, we’re going to take a closer look at just one of these
a planetary nebula that, unlike many others
doesn’t in fact look anything like a planet
Known by its catalogue number NGC 5189
this planetary nebula might not sound very exciting
When it was discovered in the 19th century
the telescopes of the day could barely make out any structure
But advances in telescope technology over a century and a half have borne fruit
For a long time, the best image of this object was
from the European Southern Observatory’s NTT
which reveals NGC 5189’s complex spiral shape
Then came a remarkable picture from the 8-metre Gemini South telescope
But if you point Hubble at it…
Well if you point Hubble at it, then you get to see some truly spectacular detail
much of which has never been seen before
And that’s of course due to Hubble’s unique vantage point
above the Earth’s atmosphere
If we zoom in close, which we can thanks to Hubble’s high resolution
then we start seeing these very dense knots in the clouds of gas
Hubble has seen these before, most famously in the Helix Nebula
Now what’s going on here is that the radiation from the dying star
is carving these knots into shape
forming these glowing bow-wave-like patterns
much like water flowing around a rock in a stream
And these are all pointing towards the centre of the nebula
The knots in NGC 5189 are a reminder of just how big planetary nebulae are
They might look insignificant here
but they are actually a similar size to the entire Solar System
The star at the centre of the nebula, a dense white dwarf
is far too small to see as anything other than a point of light
even though it is roughly the size of the Earth
NGC 5189’s spiral shape is perhaps its most obvious feature
leading to its nickname of ‘the Spiral Planetary Nebula’
The structure is reminiscent of water coming from a lawn sprinkler
and it’s probably due to the star rotating and wobbling as it expels matter
Similar structures have been seen before
especially in planetary nebulae with binary stars at their centres
but whether there are two stars or just one at the centre of NGC 5189
remains an open question
And so its shape and the science that lies behind it
remain a fascinating area for astronomers to study
This is Dr J, signing off for the Hubblecast
Once again, nature has surprised us beyond our wildest imagination
Hubblecast is produced by ESA/Hubble at the European Southern Observatory in Germany
The Hubble mission is a project of international cooperation between NASA and the European Space Agency
www.spacetelescope.org
Transcribed by ESA/Hubble. Translation --