Waaay back when I took a Nuclear Chemistry course in college, we learned about how elements heavier than iron are formed in supernovae, thanks to the tremendous enegies released, which allows fusion of larger nuclei.
We also learned that, although all the trans-uranium elements are radioactive and usually have short half lives, there are predicted to be some superheavy elements occupying an “island of stability” in the periodic table. These elements would have longer half lives, and might even be stable. Currently, I believe these elements are predicted to have atomic numbers 120, 124, and 126 – significantly heavier than any man-made elements.
My question is: do supernovae produce energies high enough to synthesize these hypothetical elements? If so, can we predict what their spectral signatures would look like well enough to detect them (assuming they exist)? This would be a very cool discovery!
The isotopes in the theoretical Island of Stability cannot be reached by neutron absorption from lighter elements, so no I don’t believe they can form in supernovae. Whether something like the breakup of a neutron star could form them, I have no idea.
Keep in mind that the “island of stability” is expects to take elements from a halflife of milliseconds to a half-life of seconds or minutes. It’s not like the island of stability is sufficient to get a planet made out of transuranic elements. Looking for these things “in the wild” is not going to be fruitful whether they can be made by stars or not.
Well, in recent months, there have been discoveries of a fair number of super-massive stars. (more than 100 stellar masses), and a whole new type of supernova, with entirely different spectral signatures. It seems that stellar mechanics still has a few unexplored avenues. However, the Trans-uranics are probably not likely to form, even at the newly elevated temperatures.
Some of the indications of observations of active galaxies and their ejecta seem to hold some promise for creation of heavy elements as well, but I don’t think heavy in that case goes much beyond the upper end of the Natural elements. Twice, in recent months some mention of close on collision of black holes, with attendant disruption of their accretion disks are reputed to create gamma ray and cosmic ray bursts of temperatures exceeded only by the big bang. It seems that energy levels are not the constraint that precludes the existence of the heavyweight nuclei, but another mechanism.