![](\"http:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2016\/02\/the_unearthly_beauty_of_the_red_rectangle\/15787323-1-eng-GB\/The_Unearthly_Beauty_of_the_Red_Rectangle_small.jpg\")
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\nStraight lines do not often crop up in space. Whenever they do, they seem somehow incongruous and draw our attention. The Red Rectangle is one such mystery object.\n<\/p>\n
\nIt first caught astronomers\u2019 attention in 1973. The star HD 44179 had been known since 1915 to be double<\/a>, but it was only when a rocket flight carrying an infrared detector was turned its way that the red rectangle revealed itself.\n<\/p>\n \nThis image was taken later, in 2007, by the Hubble Space Telescope\u2019s Advanced Camera for Surveys<\/a>. It focuses on wavelengths of red light, in particular highlighting the emission from hydrogen gas.\n<\/p>\n \nThis particular emission has been displayed in red. A second, broader range of orange\u2013red light has also been recorded, and, to increase the contrast, this light has been colour coded blue on the image.\n<\/p>\n \nThe Red Rectangle is some 2300 light-years away in the constellation of Monoceros<\/a>. It arises because one of the stars in HD 44179 is in the last stages of its life. It has puffed up as the nuclear reactions at its core have faltered, and this has resulted in it shedding its outer layers into space.\n<\/p>\n \nSuch a cloud of gas is known erroneously as a planetary nebula because Hanoverian astronomer William Herschel thought they look a bit like the pale disc of Uranus, the planet he had discovered.\n<\/p>\n \nThe X-shape revealed in this image suggests that something is preventing the uniform expansion of the star\u2019s atmosphere. Instead, a thick disc of dust probably surrounds the star, funnelling the outflow into two wide cones. The edges of these show up as the diagonal lines. Thankfully, while that explains the mystery of the object, it does not detract from its unearthly beauty.\n<\/p>\n \nThis image was first published<\/a> in June 2010.<\/p>\n","protected":false},"excerpt":{"rendered":" \nStraight lines do not often crop up in space. Whenever they do, they seem somehow incongruous and draw our attention. The Red Rectangle is one such mystery object.\n<\/p>\n \nIt first caught astronomers’ attention in 1973. The star HD 44179 had been known since 1915 to be double<\/a>, but it was only when a rocket flight carrying an infrared detector was turned its way that the red rectangle revealed itself.\n<\/p>\n \nThis image was taken later, in 2007, by the Hubble Space Telescope’s Advanced Camera for Surveys<\/a>. It focuses on wavelengths of red light, in particular highlighting the emission from hydrogen gas.\n<\/p>\n \nThis particular emission has been displayed in red. A second, broader range of orange–red light has also been recorded, and, to increase the contrast, this light has been colour coded blue on the image.\n<\/p>\n<\/p>\n