Hubble’s latest snapshot of galaxy IC 758, 60 million light-years away, reveals a cosmic mystery. A supernova’s explosive past could unlock secrets of star formation and galactic evolution.

The Hubble Space Telescope has captured an image of a barred spiral galaxy IC 758 at a distance of 60 million lightyears in the constellation of Ursa Major or the Great Bear. In 1999, the supernova designated as SN 1999bg exploded in the galaxy, which was the violent explosion marking the end of a star much more massive than the Sun.

Astronomers do not know how massive this progenitor star was. The Hubble observations will be used to measure the masses of the stars in the neighbourhood of the supernova, which in turn will allow scientists to estimate the mass of the star that went bust.

These follow-up observations will also allow astronomers to determine if the progenitor star had any companions, which can provide additional clues about the life and death of the star. Such supernova explosions can reshape the stellar neighbourhoods, by stirring the gas and dust in the environment, the raw material from which new stars are born.

The explosions can scatter the star forming material, preventing the formation of dense stars, or increase the density of the matter by compressing it, encouraging the formation of new stars. The ejected material itself can be recycled into new stars.

Structure of IC 758

The central bar is believed to play a role in the transportation of gas and dust to the supermassive black hole lurking in the core of the galaxy. The younger, bluer stars occupy the fringes of the galaxy, while the older, redder stars are towards the centre.

The soft, spiral arms are not physical structures, but density patterns formed by stars moving in and out of the spiral arms as they rotate around the core of the galaxy, similar to cars moving in traffic. It is only recently that astronomers managed to solve what was known as the ‘winding problem’.

Source: News9live.