GERMANY – A team of scientists from the Technical University of Berlin (Germany) has discovered the footprint of the most recent supernovae which is also closer to Earth. A previous supernova occurred 1.5 million years ago to about 96 parsecs away in the constellation Libra and, a little earlier, about 800,000 years, in the constellation Wolf, 91 parsecs.

To identify them, experts checked against the records of a radioactive isotope of iron (⁶⁰Fe) found in the depths of the Pacific Ocean (about 4,000 meters deep) that is not found naturally in the earth. However, supernovae do generate a copious amount of ⁶⁰Fe. The isotope has a half-life of 2.6 million years,

The data from this rare isotope of iron were compared with those of Hipparcos astrometric satellite of the European Space Agency, which in the 90s measured the positions and velocities of thousands of stars in our environment. The examination of both information through a computer simulation model analyzing the transport of the isotope from these supernovae, it was confirmed they are undoubtedly the most recent and closest to us. The nearest had a mass of about 92 times greater than the Sun and the other of 8.8 times.

The study, which was published in the journal Nature provides a breakthrough in the formation of stars in the “Local Bubble”, a cavity of the Milky Way with low density and with about 600 x 600 x 1200 light years extension which also runs our solar system.