Sitting in Scorpius, this object has long been a favourite of both amateur and professional astrophotographers.<\/p>\n
But Hubble Space Telescope<\/a> images presented in a recent paper, covering more than a decade of observations, are the most detailed and interesting yet.<\/p>\n Like all planetary nebulae<\/a>, the large wings of the Butterfly Nebula are formed from gas expelled from the object\u2019s central star, typically a Sun-like star which is entering the last stages of its life.<\/span><\/p>\n The brightness and dynamism of this particular nebula, in which changes in the gas can be seen in images taken just a year or two apart, suggest that it has a particularly hot and massive central source.\u00a0<\/span><\/p>\n There is certainly plenty of ejected stuff in the system.<\/p>\n Carefully puzzling out the geometry of what we\u2019re seeing, deriving the three-dimensional shape of the nebula from its two-dimensional image, flattened against the sky like a butterfly pinned to a board, suggests that somewhere between 0.1 and one solar masses of gas make up the nebula we see today.<\/p>\n The next problem is explaining the complexity of the structure itself.<\/p>\n Like many planetary nebulae the Butterfly is broadly symmetrical, yet it is anything but simple.<\/p>\n The images show what the authors call \u2018wedges\u2019, stretching out from the centre, and between them clumps of material.<\/p>\n Several seem to have grown comet-like tails, the result of the action of the powerful winds still flowing from that elusive central source.<\/p>\n Images that cover a wider field than Hubble show an extended \u2018breakout\u2019 tail, one of the largest features seen in any planetary nebula, stretching off to the northwest.<\/p>\n Many of these structures are still moving rapidly and, working backwards, the observations suggest that they are the product of a violent period that began 2,300 years ago and lasted perhaps for 1,400 years.<\/p>\n It started with the ejection of what is now a long northwestern streamer, which was followed a few hundred years later by the other wedges.<\/p>\n Recent activity, in the last couple of hundred years, has further stirred things up.<\/p>\n Rather colourfully, the authors compare the multiple ejection events from the unseen central star to \u2018a series of metaphorical sneezes and a protracted wheeze, akin to a fire-breathing dragon\u2019.<\/p>\n Dragon or not, changes on such a short timescale imply that whatever lurks at the centre of the nebula is evolving quickly.<\/p>\n It\u2019s possible that there are multiple stars at the centre, with the motions of a binary star<\/a> or even a triple star sculpting the nebula<\/a>.<\/p>\n But what\u2019s seen makes most sense if at least one star at the Butterfly\u2019s heart is massive, with a luminosity perhaps equivalent to that of a thousand Suns.<\/p>\n Such large objects live their lives on fast-forward, and so we are treated to an accelerated view of the end of stellar life as these stars<\/a>\u2019 convulsions produce a nebula of wonderful and confusing complexity.<\/p>\n![\""Hubble\"](\""https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2023\/05\/STScI-01EVSTBWH6P5BDMZ5XMWG365C7-d820576-e1684397393377.png?quality=90&resize=620%2C551"\" "\\"\"Hubble\\"\/")
<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>![\""Ancient\"](\""https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2022\/05\/04.iotw2215a-7edd8d6.jpg?quality=90&resize=620%2C611"\" "\\"\"Ancient\\"\/")
<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>![\""Butterfly\"](\""https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/08\/ButterflyNebula-7e4a9ff.jpg?quality=90&resize=620%2C519"\" "\\"\"Butterfly\\"\/")
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