Free Astronomy Magazine May-June 2015

STELLAR EVOLUTION tographic plates of the Palomar Observatory Sky Survey. In the early ‘80s there was, though, a first breakthrough: studies carried out mainly in H-alpha (red light) by Michael M. Shara, Anthony F. J. Moffat and Ronald F. Web- bink with the Multiple Mirror Telescope (Cerro Tololo International Observatory) and the Canada-France-Hawaii Telescope re- vealed, in the location of Nova Vul 1670, a gaseous ring with some subcondensations and possible jets of matter perpendicular to the ring, maybe aligned with the poles of what appeared to be a central star envel- oped in a gaseous cocoon, preventing re- searchers from determining the real nature of the star. The team calculated the distance of this object in approximately 1800 light- years, and in knowing this it derived an absolute magnitude of 10.4, which is about 6 mag (or 244 times) fainter than a typi- cal old nova. Considering also that the dif- ference between the nova’s maximum and minimum apparent magnitude has over the centuries reached 18 mag, Shara and colleagues have fundamentally confirmed W ide angle image showing the sky around the area where the Nova Vul 1670 explod- ed, with at its centre the almost indiscernible remnant left by the event. [ESO/ Digitized Sky Survey 2, Davide De Martin]