But not only the spatial distributions of titanium and iron resemble those in Cas A. Also the total amounts of these elements, their expansion velocities, and the velocity of the neutron star are in amazing agreement with those of Cas A. "This ability to reproduce basic properties of the observations impressively confirms that Cas A may be the remnant of a neutrino-driven supernova with its violent gas motions around the nascent neutron star", concludes H.-Thomas Janka.
But more work is needed to finally prove that the explosions of massive stars are indeed powered by energy input from neutrinos. "Cas A is an object of so much interest and importance that we must also understand the spatial distributions of other chemical species such as silicon, argon, neon, and oxygen", remarks Ewald Müller, pointing to the beautiful multi-component morphology of Cas A revealed by 3D imaging. Just having one example is also not enough for making a fully convincing case. Therefore the team has joined a bigger collaboration to test the theoretical predictions for neutrino-driven explosions by a close analysis of a larger sample of young supernova remnants. Step by step the researchers thus hope to collect evidence to be able to settle the long-standing problem of the supernova mechanism.
Interactive 3D visualization of the spatial distribution of 56Ni ejected in the neutrino-driven supernova simulation of Fig. 1.
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Production and Distribution of 44Ti and 56Ni in a Three-dimensional Supernova Model Resembling Cassiopeia A
ApJ 842 13
MPG Press Release
Radioactive elements in Cassiopeia A suggest a neutrino-driven explosion
RIKEN Press Release