Dual System HR 5171
The giant star, which is 1,300 times the size of our Sun, was discovered at a distance of 12,000 light years from Earth. This is one of the ten largest known stars in our galaxy. The yellow supergiant is even heavier than the famous star heavyweight Betelgeuse.
"New observations have also shown that this star has a close star partner, which was a real surprise to us," says Olivier Chénaune, from the Cote d'Azur Observatory in Nice, France. "These two stars are so close that they physically touch and the whole system resembles a giant peanut."
This recent observation was made by the Chenot team, which uses data from the Very Large Telescope Interferometer (VLTI) of the European Southern Observatory in Chile. The data obtained is the result of sixty years of observation. They helped to understand that the main star in the dual system - HR 5171A, is undergoing very rapid changes and is entering a very short stage in its life cycle.
Changes in HR 5171 A for three time periods Yellow supergiants are rare stellar objects. At the moment, about ten such objects have been found in the Milky Way, so they are considered cosmic jewels. The yellow supergiant is actually a short phase that massive stars must pass before they burn all their fuel. During this phase, fierce internal convulsions carry a huge amount of stellar gases into space, creating a vast nebula around the star.
Although the star is relatively far from Earth, HR 5171 can be observed with the naked eye on a clear night in the constellation Centaurus.
Over the past 40 years, HR 5171A has become bigger and cooler. Her star partner HR 5171 B is slightly hotter and is observed before HR 5171 A when they perform their intimate orbital waltz (for this reason HR 5171 is known as the “eclipsing” double system).
“The satellite that we discovered is significant because it can influence the fate of HR 5171 A, clearing the outer layers and changing its evolution,” says Chenot.