A study that answers major questions regarding supernovas – colossal explosions of stars whose spectacular luminous flashes serve to establish distances – was published in the latest edition of Nature Magazine by a group of experts. These include astronomers Mario Hamuy and Gastón Folatelli from the Department of Astronomy of the Universidad de Chile and the Millennium Nucleus for Supernova Studies (MCSS).
The characteristics of these veritable “cosmic beacons” are very special, because they also propagate at high speed as a result of the detonations. And it is precisely these expansion speeds that display different behaviors, which has led specialists to ask themselves for decades whether supernovas are really reliable to determine distances.
The work of Hamuy and Folatelli shows that type Ia supernova explosions are not perfectly symmetrical and that the differences in the observed speeds are due to the direction from which they are observed, which varies randomly from supernova to supernova. This finally clarifies the origin of the diversity of speeds exhibited by this type of supernova.
The conclusions of the study, also conducted by scientists based in places as dissimilar as Japan, Germany, the United States and Italy, is very good news for astronomers, because the effect of the angle of vision is annulled when there is a large cluster of supernovas. Therefore, the use of type Ia supernovas to measure distances can now cease to be a concern.
To arrive at these results, the researchers used speed measurements (on the basis of their spectra) of 20 supernovas, taken when the object was at close to its maximum brilliance and between six months and one year later. The Department of Astronomy of the Universidad de Chile explained that the data included supernovas that appeared within the last 25 years.
“Our observations using world-class telescopes installed in the north of Chile, such as the eight-meter Gemini, and telescopes from the Las Campanas and La Silla observatories, were essential to this discovery”, stressed Mario Hamuy.
Chile is renowned for possessing the clearest skies on the world, which has made it a pole for astronomical development.