A supernova in M82

On January 22, a supernova was discovered in M82 (SN 2014J) in one of the closest galaxies to the Milky Way, “only” 4 Megaparsec (4 million parsecs) away.

Image of Supernova in M82 obtained in Loiano (INAF Bologna) with the telescope GD Cassini 1.5 Meters (tool BFOSC) January 23. G. Altavilla, R. Gualandi.


On January 22, a supernova was discovered in M82 (SN 2014J) in one of the closest galaxies to the Milky Way, “only” 4 Megaparsec (4 million parsecs) away. The discovery was made during a demonstration to a group of students in London: M82 is also visible in small amateur telescopes and is among the galaxies that were photographed by amateur astronomers. Supernovae that are so close are rare, almost one every three to four years.

The analysis of the spectrum of SN 2014J had verified that it is an IA SN Type and several images show the evolution of supernova from a few hours after the explosion. This type of stellar explosion is catastrophic: the progenitor star is completely destroyed and the material of which it is composed hurled into the surrounding space at speeds of 10-20,000 km / s. The explosion leaves no compact remnant as it does for other types of supernovae (core -collapse) that give rise to neutron stars. When they reach the peak of brightness, not only IA Supernovae are extremely bright and therefore visible to billions of light years away but also have an intrinsic luminosity constant. This property makes them “standard candles” of exceptional utility. Saul Pelmutter, Adam Riess and Brian Schmidt studying the brightness of IA Supernovae – to large redshifts have discovered the accelerating expansion of the Universe and have received the Nobel Prize for Physics in 2012.

Paradoxically, despite the enormous importance that the IA Supernovae – have in the modern cosmological debate, yet we do not know with certainty the type of binary system that produces these explosions, if the coalescence (fusion) of two white dwarfs or the explosion of a dwarf white, which increases the outer layers of a nearby star.

“The explosion of a IA SN so close is an extraordinary opportunity to study in detail the progenitor of SN -says Maria Teresa Botticelli (Capodimonte Observatory, INAF -Napoli) – we are analyzing images acquired before the explosion with space telescopes such as the Hubble Space Telescope and Spitzer. Unfortunately, from a first analysis of the HST images, it has not been possible to detect directly the progenitor of SN which is probably hidden by a blanket of dust. Once past the initial disappointment, we jumped at the new challenge: trying to look beyond the dust clouds, with images obtained in the ‘infrared’. “We are pursuing the same goal, namely the study of the progenitor, with a complementary approach – adds Stefano Benetti (INAF, Padova) – through high-resolution spectroscopic observations with the Galileo National Telescope, Supernova, which will allow us to study the “distributed interaction between the interstellar medium around the progenitor star and the intense radiation field produced by the explosion and the ejecta expelled from SN.”

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