Astronomers may have found the elusive progenitor to a Type Ic supernova

This long-sought progenitor star was identified in an image captured by Hubble in 2007

Two teams of astronomers may finally have found the elusive progenitor star to a special type of supernova known as a Type Ic supernova.

According to NASA, this progenitor could be among biggest known, and was uncovered after detailed investigation of the archival data of NASA's Hubble Space Telescope.

A supernova is the largest and brightest explosion known to take place in space. This super-powerful explosion occurs when a star reaches the end of its life. The event is so powerful that it can briefly outshine an entire galaxy. However, the last observed supernova in the Milky Way was discovered by Johannes Kepler in 1604.

Scientists believe that a Type Ic supernova detonates after its massive progenitor is stripped of its outer layers of helium and hydrogen. These stars could be about 30 times (or more) heavier than our Sun. Up until now, scientists have failed to identify any massive progenitor to a Type Ic supernova in pre-explosion images.

Fortunately, in 2017 astronomers were able to capture a cosmic event in which a nearby star completed its life as a Type Ic supernova (called SN 2017ein). This supernova was located about 65 million light-years away in the centre of the spiral galaxy NGC 3938.

Two teams of astronomers - one led by Schuyler Van Dyk of the California Institute of Technology in Pasadena and the other led by Charles Kilpatrick of the University of California, Santa Cruz - started investigating the archive of Hubble images and were able to identify the precursor to SN 2017ein in a Hubble image captured in 2007.

SN 2017ein was first noticed in May 2017 by Tenagra Observatories in Arizona. In June 2017, Van Dyk's team imaged the young supernova using Hubble's Wide Field Camera 3 and then used the image to identity the possible progenitor star in an archive mage captured by Hubble's Wide Field Planetary Camera 2 in December 2007. In that archive image, the progenitor star was seen sitting in one of the spiral arms of the host galaxy.

Kilpatrick's team also observed the supernova in June 2017 in infrared images captured by a telescope at the W. M. Keck Observatory in Hawaii. The astronomers then analysed the same 2007 archival Hubble image and identified the possible supernova progenitor.

Both teams caution that the identity of the progenitor star will be finally confirmed only after the supernova fades in about two years. At that time, they will be able to precisely calculate the mass and the brightness of the progenitor after separating the light of the supernova from the light of other stars in its environment.