?Astronomers have seen for the first time a star devouring a planet… The future of the Earth
Scientists already knew that old stars eventually gobble up nearby planets. But they had never witnessed this cosmic feast directly before.
“ We see the future of the Earth ”. This is the reaction of Kishalay De, a postdoctoral researcher at the Kavli Institute for Astrophysics and Space Research at MIT, about the exceptional phenomenon that he and his team witnessed. They watched a Sun -like star swallow a planet and regurgitate a burst of light and energy. Scientists predict that our Sun will do the same in 5 billion years, swallowing up Mercury, Venus and possibly Earth.
The planetary sinking in question occurred in our galaxy, some 12,000 light-years away, near the constellation of Aquila. In May 2020, astronomers detected the explosion of a star, a hot gas giant roughly the size of Jupiter . It became more than 100 times brighter within 10 days, before quickly fading. This flash was followed by a colder and longer lasting signal.
Disturbing infrared data
Kishalay De explains that he first thought it was a nova explosion within a stellar binary . But by pushing his analysis, he found no release of helium and hydrogen typical of this kind of event. Instead, he found signs of " peculiar molecules " that are only detected at very cold temperatures. Perplexed, he decided to put this study on hold while he completed his thesis at the California Institute of Technology (Caltech).
A year later, after joining MIT, he got back to work with his colleagues using data from that same star taken with an infrared camera that reveals signals emitted by cooler materials. " This infrared data knocked me out of my chair ," explains the young researcher. The detected material was probably gas thrown by the star into space. It condensed into dust cool enough to be detected in the infrared.
Detect other similar events
The researchers completed their analysis using NASA's Neowise space telescope , which had also detected the infrared signature of this star. “ The infrared observations were one of the main clues that we were observing a star engulfing a planet ,” says Viraj Karambelkar, a postgraduate student at Caltech and co-author of the study published in the journal Nature .
At the end of this investigation, the team of researchers worked out the most probable scenario. The bright, burning flash initially seen was likely the planet's final moments dragged into the expanding atmosphere of its dying star. By brushing the surface of the star, the planet ejected hot gas into space which cooled, forming dust. Then, explains Kishalay De, “ the planet plunged into the heart of the star and was swallowed whole. In doing so, she transferred energy to the star. The star blew up its outer layers to get rid of the energy. It dilated and cleared up”.
According to him, the fact of having been able to witness this planetary engulfment will now facilitate the search for similar events which should teach us more about the fate of our planet.
Source : websites