Cosmic Mystery: VLT Captures Sudden Disappearance Of A Massive Star

Eddie Gonzales Jr. – MessageToEagle.com – Using the European Southern Observatory’s Very Large Telescope (VLT), astronomers have discovered the absence of an unstable massive star in a dwarf galaxy.

The star could become less bright and partially obscured by dust, or star collapsed into a black hole without producing a supernova, according to astronomers.

This illustration shows what the luminous blue variable star in the Kinman Dwarf galaxy could have looked like before its mysterious disappearance. Credit: ESO/L. CalçadaThis illustration shows what the luminous blue variable star in the Kinman Dwarf galaxy could have looked like before its mysterious disappearance. Credit: ESO/L. Calçada

“If true,” says team leader and Ph.D. student Andrew Allan of Trinity College Dublin, Ireland, “this would be the first direct detection of such a monster star ending its life in this manner.”

Many astronomers have studied this star between 2001 and 2011.

Located in the Kinman Dwarf galaxy, some 75 million light-years away in the constellation of Aquarius, the star was in a late stage of its evolution, and it was planned to find out more about how very massive stars end their lives, and the object in the Kinman Dwarf seemed like the perfect target.

The Kinman Dwarf galaxy is too far away for astronomers to see its individual stars, but it was possible to observe the one that unfortunately disappeared.

“Instead, we were surprised to find out that the star had disappeared!” says Allan, who led a study of the star published today in Monthly Notices of the Royal Astronomical Society.

From 2001 to 2011, the light from the galaxy consistently showed evidence that it hosted a ‘luminous blue variable’ star some 2.5 million times brighter than the Sun.

But the traces of this star were absent from the data the team collected in 2019.

“It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion,” says Allan.

The group first turned the ESPRESSO instrument toward the star in August 2019, using the VLT’s four 8-meter telescopes simultaneously, the star was not found.

“We may have detected one of the most massive stars of the local Universe going gently into the night,” says team-member Jose Groh, also of Trinity College Dublin.

The old data indicated that the star in the Kinman Dwarf could have been undergoing a strong outburst period that likely ended sometime after 2011. Luminous blue variable stars such as this one are prone to experiencing giant outbursts over the course of their life, causing the stars’ rate of mass loss to spike and their luminosity to increase dramatically.

Based on their observations and models, the astronomers have suggested two explanations for the star’s disappearance and lack of a supernova, related to this possible outburst. The outburst may have resulted in the luminous blue variable being transformed into a less luminous star, which could also be partly hidden by dust. Alternatively, the team says the star may have collapsed into a black hole, without producing a supernova explosion.

This would be a rare event: our current understanding of how massive stars die points to most of them ending their lives in a supernova.

Future studies are needed to confirm what fate befell this star.

Written by Eddie Gonzales Jr. – MessageToEagle.com Staff