1 00:00:00,000 --> 00:00:04,000 A planetary nebula represents one of the final stages 2 00:00:04,000 --> 00:00:06,000 in the life of a star like our own Sun 3 00:00:06,000 --> 00:00:11,000 Near the end of its life, before it consumes all of its remaining fuel 4 00:00:11,000 --> 00:00:14,000 a star expels its outer layers 5 00:00:14,000 --> 00:00:17,000 These are then excited by the radiation of the star 6 00:00:17,000 --> 00:00:22,000 and begin to glow brightly, showing intricate and fascinating structures 7 00:00:22,000 --> 00:00:26,000 that scientists are still trying to fully understand 8 00:00:42,000 --> 00:00:48,000 Hubblecast episode 61: a tour of NGC 5189 9 00:00:48,000 --> 00:00:51,000 Presented by Dr J, aka Dr Joe Liske 10 00:00:55,000 --> 00:00:57,000 Hi and welcome to the Hubblecast 11 00:00:57,000 --> 00:01:02,000 In previous episodes, we’ve looked at a lot of Hubble’s images of planetary nebulae 12 00:01:02,000 --> 00:01:07,000 and we’ve talked about how they tell us about the ultimate fate of our own Sun 13 00:01:07,000 --> 00:01:11,000 In this episode, we’re going to take a closer look at just one of these 14 00:01:11,000 --> 00:01:14,000 a planetary nebula that, unlike many others 15 00:01:14,000 --> 00:01:17,000 doesn’t in fact look anything like a planet 16 00:01:19,000 --> 00:01:24,000 Known by its catalogue number NGC 5189 17 00:01:24,000 --> 00:01:29,000 this planetary nebula might not sound very exciting 18 00:01:32,000 --> 00:01:34,000 When it was discovered in the 19th century 19 00:01:34,000 --> 00:01:39,000 the telescopes of the day could barely make out any structure 20 00:01:39,000 --> 00:01:45,000 But advances in telescope technology over a century and a half have borne fruit 21 00:01:48,000 --> 00:01:52,000 For a long time, the best image of this object was 22 00:01:52,000 --> 00:01:55,000 from the European Southern Observatory’s NTT 23 00:01:55,000 --> 00:02:00,000 which reveals NGC 5189’s complex spiral shape 24 00:02:01,000 --> 00:02:06,000 Then came a remarkable picture from the 8-metre Gemini South telescope 25 00:02:06,000 --> 00:02:09,000 But if you point Hubble at it… 26 00:02:11,000 --> 00:02:16,000 Well if you point Hubble at it, then you get to see some truly spectacular detail 27 00:02:16,000 --> 00:02:19,000 much of which has never been seen before 28 00:02:19,000 --> 00:02:22,000 And that’s of course due to Hubble’s unique vantage point 29 00:02:22,000 --> 00:02:24,000 above the Earth’s atmosphere 30 00:02:26,000 --> 00:02:29,000 If we zoom in close, which we can thanks to Hubble’s high resolution 31 00:02:29,000 --> 00:02:33,000 then we start seeing these very dense knots in the clouds of gas 32 00:02:36,000 --> 00:02:40,000 Hubble has seen these before, most famously in the Helix Nebula 33 00:02:42,000 --> 00:02:46,000 Now what’s going on here is that the radiation from the dying star 34 00:02:46,000 --> 00:02:49,000 is carving these knots into shape 35 00:02:49,000 --> 00:02:52,000 forming these glowing bow-wave-like patterns 36 00:02:52,000 --> 00:02:56,000 much like water flowing around a rock in a stream 37 00:02:56,000 --> 00:02:59,000 And these are all pointing towards the centre of the nebula 38 00:03:02,000 --> 00:03:09,000 The knots in NGC 5189 are a reminder of just how big planetary nebulae are 39 00:03:09,000 --> 00:03:12,000 They might look insignificant here 40 00:03:12,000 --> 00:03:18,000 but they are actually a similar size to the entire Solar System 41 00:03:20,000 --> 00:03:23,000 The star at the centre of the nebula, a dense white dwarf 42 00:03:23,000 --> 00:03:28,000 is far too small to see as anything other than a point of light 43 00:03:28,000 --> 00:03:32,000 even though it is roughly the size of the Earth 44 00:03:34,000 --> 00:03:39,000 NGC 5189’s spiral shape is perhaps its most obvious feature 45 00:03:39,000 --> 00:03:42,000 leading to its nickname of ‘the Spiral Planetary Nebula’ 46 00:03:44,000 --> 00:03:46,000 The structure is reminiscent of water coming from a lawn sprinkler 47 00:03:46,000 --> 00:03:52,000 and it’s probably due to the star rotating and wobbling as it expels matter 48 00:03:52,000 --> 00:03:54,000 Similar structures have been seen before 49 00:03:54,000 --> 00:03:59,000 especially in planetary nebulae with binary stars at their centres 50 00:03:59,000 --> 00:04:04,000 but whether there are two stars or just one at the centre of NGC 5189 51 00:04:04,000 --> 00:04:06,000 remains an open question 52 00:04:06,000 --> 00:04:10,000 And so its shape and the science that lies behind it 53 00:04:10,000 --> 00:04:14,000 remain a fascinating area for astronomers to study 54 00:04:15,000 --> 00:04:17,000 This is Dr J, signing off for the Hubblecast 55 00:04:17,000 --> 00:04:22,000 Once again, nature has surprised us beyond our wildest imagination 56 00:04:22,000 --> 00:04:25,000 Hubblecast is produced by ESA/Hubble at the European Southern Observatory in Germany 57 00:04:28,000 --> 00:04:31,000 The Hubble mission is a project of international cooperation between NASA and the European Space Agency 58 00:04:34,000 --> 00:04:35,000 www.spacetelescope.org 59 00:04:35,000 --> 00:04:38,000 Transcribed by ESA/Hubble. Translation --