It is our most recent cosmic history . A team of scientists from the Technical University of Berlin (Germany) has discovered the footprint of the most recent supernovae that are also closest to Earth. A healthy supernova occurred 1.5 million years ago about 96 parsecs away in the constellation Libra, and a little earlier, about 800,000 years ago, another did so in the constellation Wolf, 91 parsecs away.
To identify them, the experts collated the records of a radioactive isotope of iron (60Fe) found in the deepest part of the Pacific Ocean (about 4,000 meters deep) that is not found naturally on Earth and therefore comes from from stellar sources of great permanence as a supernova.
The data on this rare iron isotope were compared with that of the Hipparcos astrometric satellite of the European Space Agency, which in the 1990s measured the positions and speeds of thousands of stars around our environment. The examination of both information by means of a computer simulation model has confirmed that these supernovae are undoubtedly the last, the most recent and close to us after analyzing the transport of the isotope from these supernovae. The closest one had a mass around 9.2 times that of the Sun and the other 8.8 times more.
The study, which has been published in the journal Nature , thus offers an advance in the formation of stars in the so-called “Local Bubble”, a cavity of the Milky Way with low density and with about 600 x 600 x 1200 light years of extension in which our solar system also runs.
