NASA/Chandra press release about the simulation made by an OAPA/UNIPA/CfA team of the nova V745 Sco

A recent press release has appeared on the NASA/Chandra website (link), dedicated to the binary system V745 Sco and the model developed by S. Orlando (INAF-Astronomical Observatory of Palermo), M. Miceli (University of Palermo) e J. J. Drake (Harvard-Smithsonian Center for Astrophysics, US), which explains the nova explosion occurred on February 6th 2014.

 

V745 Sco is a binary system composed by a red giant and a white dwarf. Because of the small separation between the two stars and the intense gravitational field of the white dwarf, part of the plasma in the atmosphere of the red giant is attracted by the white dwarf accreting on its surface. When the white dwarf has accreted enough mass, a thermonuclear explosion is ignited, which causes a rapid brightening of the system called “nova”. On February 6th 2014, V745 Sco has brightened by a factor of a thousand in optical, slowly fading in nine days.

 

The nova explosion was observed by several telescopes, and one of the most surprising results was that the explosion was not isotropic, with most of the material being ejected along the line of sight. This property of the nova was explained by the theoretical work led by S. Orlando: in the equatorial plane the ejecta encountered a pre-existing disk-like density enhancement, while in the polar direction the blast expanded freely. The total mass of the ejecta was about one tenth of the Earth mass, less than the mass accumulated onto the white dwarf surface necessary to ignite the nova. The white dwarf is thus accumulating mass from its companion. If enough mass will be accreted, in future the system will explode in a Type I Supernova.

 

A model of the simulation for 3D printers can be downloaded here.

 

The figure (link) shows the model of the nova explosion, with all the components of the system included in the simulation. The size of the white dwarf is exaggerated for the visualization.