A Nearby Supernova: Recipe for Rocky Planets ⚡ экспресс
The abundance of Earth-like planets is a key question in astronomy. The formation of terrestrial planets in our Solar System was driven by heat from the decay of short-lived radionuclides, primarily ²⁶Al, which were likely delivered by a nearby supernova. However, previous models couldn't explain the observed abundances of these isotopes in meteorites without destroying the protosolar disk. The 'immersion' mechanism is proposed: in the supernova's shock wave, reactions with cosmic rays generate ²⁶Al at the right concentration already at a distance of about 1 parsec, preserving the disk. According to estimates, solar-mass stars in clusters experience on average at least one such event within 1 pc. This suggests that Solar System-like levels of short-lived radionuclides and the processes for forming rocky planets are much more widespread than previously thought.
Just as yeast transforms flour into airy dough, a radioactive 'seasoning' from a supernova helps mold a rocky planet. But the dosage must be perfect: too much and the disk of cosmic dust gets blown away; too little and the planet remains loose and cold. Previously, it was thought that the explosion had to be so close that it would inevitably destroy the embryonic planetary system. However, new research has revealed an elegant trick: its invisible rays pierce the disk, collide with matter, and fabricate radioactive aluminum-26 right on the spot. At a distance of one parsec (about the distance to Proxima Centauri), the disk is not destroyed but instead receives exactly the amount of aluminum-26 found in meteorites. Calculations show that in typical stellar nurseries, at least one supernova is located at this distance. This means the recipe for forming exoplanets like Earth is not a cosmic fluke—it's the rule. The heat from aluminum-26, which has a half-life of just 717,000 years, melts the interior and separates the planet into core and crust. Perhaps this is exactly how our Earth came to be.
🎯 The heat from aluminum-26 melted the first asteroids, giving them a core and crust—like miniature Earths long before planets were born.