COMMENTS ON THE OBJECT :

Chaotic in appearance, these filaments of shocked gas visible in the Earth’s sky towards the constellation Swan form the western part of the Veil Nebula. Taken as a whole, the Veil Nebula is all that remains of a massive Milky Way star. More than 5000 years ago, this star exploded as a supernova. The shock wave then began to propagate through the interstellar medium, pushing ahead of it and ionizing the matter encountered along the way. These filaments are a bit like the ripples that form on the surface of a pond when the fall of a stone clouds its surface. The intense radiation from the supernova has also ionized the atoms that make up the interstellar material, with hydrogen emitting red, sulphur green and oxygen blue when they recover their electrons. At that time, the expanding cloud was certainly as bright as a crescent moon, and remained visible for several weeks. Also known as the Swan’s Loop, the Veil Nebula now extends from one end to the other over an apparent field of 3°, the equivalent of 6 full moons. This translates into a diameter of 70 light-years at the estimated distance of 1500 light-years from Earth. This image covers only one third of this field. Known as the Pickering Triangle in the tradition that the honours of discovery should go to the director of the observatory, this triangular complex of filaments should in all fairness be known as Fleming’s Volutes, after Williamina Fleming, the woman who actually discovered it on a photographic plate.