For the first time, researchers have observed how a star devoured a planet. So far, one has only observed the immediate prehistory or a star shortly after such an event. The observation of the process itself, which has now been made public, is a first, writes the Massachusetts Institute of Technology (MIT). The violent end of the exoplanet took place about 12,000 light years away from us, near the constellation Eagle. What the research group observed there will also happen to our earth in the distant future: When the sun reaches the end of its development in about five billion years, it will swallow up the inner planets in the same way – including our homeland.
Violent demise of a gas giant
The star first drew attention to itself with an enormous increase in brightness. For about 10 days in May 2020 it was about 100 times brighter than before, after which it quickly got darker again. While such outbreaks are observed more often, it was unusual in this case that a “colder, longer-lasting signal” remained measurable afterwards. At first it was assumed that the star explosion destroyed a second star, but the data collected did not match that. When infrared measurements were evaluated a year later, it turned out that the total amount of energy emitted was surprisingly small.
Because the total energy released was only about a thousandth of the energy that has been measured in such an explosion to date, the engulfed object would also have to be about a thousand times smaller than any known star. And coincidentally, Jupiter has about one-thousandth the mass of our sun. It was at this point that the research team realized they had witnessed an exoplanet crash into a star. The bright, hot burst is likely due to the final moments of a Jupiter-sized gas giant being pulled into the dying star. The outermost shell of the star was thrown away and turned into cold dust.
“What we’re seeing is the future of Earth,” says study leader Kishalay De of the Kavli Institute for Astrophysics and Space Research at MIT. Similarly, if another civilization were to observe the Sun from 10,000 light-years five billion years from now, they would see the star suddenly brighten as it engulfed the Earth. Currently, such a process should take place in the Milky Way several times a year, the group still thinks. In future surveys they should be found as routine. The research work was published as a cover story in the current issue of the journal Nature.