International group of astronomers, lead by Brent Miszalski (SAAO) with collaborators from the Copernicus Center (Joanna Mikołajewska and Krystian Iłkiewicz) and KU Leuven, using SALT telescope, has discovered a binary star system in The Hourglass Nebula. The SALT discovery of two stars orbiting each other every 18.15 days in The Hourglass Nebula gives new insights into how a wide variety of close binary stars and hourglass-shaped nebulae may form. High resolution spectroscopic obserwations allow to determine the properties of the system. It favoures common envelope model rather then classical nova for the formation and properties of the nebula.
More information in the press release on SALT web page (press release) and the original paper (oryginal paper).
Picture: the Hourglass Nebula as viewed by the Hubble Space Telescope in the light of ionized nitrogen (represented by red), hydrogen (green), and doubly-ionized oxygen (blue). A remarkable new SALT discovery has proven the ionizing star to be a binary system. Image credit: Raghvendra Sahai and John Trauger (JPL), the WFPC2 science team, and NASA.
