For the first time in history, astronomers have managed to get a detailed image of a star outside the Milky Way. It is located 160,000 light-years away from Earth and is a red supergiant.
To date, astronomers have managed to obtain several dozen images of the surfaces of other stars, on which it is possible to distinguish individual details. These are mostly giant stars, hundreds or even thousands of times the size of our Sun. However, the task of obtaining a similar image of a star that is in another galaxy seemed almost impossible until recently.
Everything has changed thanks to the technical capabilities of the European Southern Observatory’s Very Large Telescope Interferometer (VLTI). It provided such impressive image clarity that it was enough to produce an image of a star in another galaxy.
The VLTI’s target was the star WOH G64. It is located in the Large Magellanic Cloud, the largest of the Milky Way’s satellite galaxies (however, recent research suggests that this may not be the case, and it is simply passing by). WOH G64 is a true giant. It is two thousand times larger than the Sun. Such an impressive size is due to the fact that it has already entered the dying phase. WOH G64 exhausted its hydrogen fuel supply and began to expand rapidly, becoming a red supergiant.
After comparing the VLTI image with previous observations of WOH G64, experts have been surprised to find that the star has grown dimmer over the past decade. This is because it ejected a large amount of material that formed an elongated dust cocoon around it. The shape of this cocoon also came as a surprise to astronomers. Based on previous observations and computer models, they thought it should look different. According to astronomers, the egg-shaped cocoon can be explained either by the giant’s process of shedding the outer layers of its atmosphere or by the influence of a yet-to-be-discovered companion.
As the star grows dimmer, it would become harder and harder to get new images of it, the science team said. However, they are hopeful that with the planned upgrade, VLTI will be up to the task.
The interest of researchers in WOH G64 is quite natural. It is one of the most extreme stars of its kind, and every abrupt change can bring it to an explosive end. The fact is that the process of shedding the outer layers is the last stage before the red supergiant collapses and becomes a supernova. No wonder astronomers want to learn as much as they can about it and see what changes giant stars undergo before they die.
Provided by ESO
