Free Astronomy Magazine May-June 2015

MAY-JUNE 2015 STELLAR EVOLUTION 1919), culminated with its explosion as a re- sult of a final helium shell flash, or perhaps a violent event not yet fully known or com- pletely unknown to us. The only sure thing is its explosive dynamics, given that materi- al was observed moving away from the cen- tre of the stellar object at speeds of a few hundred km/s. And it is equally certain that the remnant of that explosion was not spotted before as a result of the very low temperature of such material, estimated at around minus 260 degrees C, which shifts the maximum light emission (if we can call it so) towards mil- limetre wavelengths and beyond, as far as to the radio domain. Some of the technolo- gies best suited to inves- tigate these regions of the electromagnetic spectrum have made significant progress only in recent years, and the first to usefully employ them on CK Vul were six researchers led by Tomasz Kami ń ski (Max-Planck-Institut für Radioastronomie, Germany), who point- ed on the enigmatic star the single dish APEX antenna of ESO (Atacama Pathfinder Experiment, ALMA’s predecessor), the eight antennas of the Submillimeter Array (SMA), located and operated in Hawaii by the Smith- sonian Astrophysical Observatory, and the huge radio telescope at Effelsberg, North Rhine-Westphalia, Germany. The observation at millimetre waves has sur- prisingly revealed that the expanding mo- lecular gas and dust associated with CK Vul are particularly varied from a chemical point of view. That environment is exceptionally rich in ni- trogen and characterized by very peculiar isotopic ratios, especially as regards to carbon, oxygen and the same ni- has also used this instrument to investigate the motions and chemical compo- sition of the ma- terial ejected by the explosion of Nova Vul 1670. [Afshin Darian]