A group of scientists reported this Wednesday that they have observed for the first time a star “swallowing” a planet, providing a preview of Earth’s expected fate in about five billion years.
When the Sun potentially engulfs the Earth, it will cause only a “minor disturbance” compared to this cosmic explosion, according to American astronomers.
It is believed that most planets come to an end when their star runs out of energy and turns into an expanding red giant.
Astronomers had seen the before and after effects of this process before, but never before had they captured a planet as it was being consumed.
Kishalay De, a postdoctoral researcher at MIT in the United States, and lead author of the new study, said the accidental discovery unfolded like a “detective story”.
“It all started about three years ago when I analyzed data from the Zwicky Transient Facility study, which captures images of the sky every night,” Kishalay De said at a news conference.
The scientist came across a star whose brightness suddenly increased more than 100 times in a 10-day period.
The star is located in the Milky Way galaxy, about 12,000 light-years from Earth, near the constellation Aquila, which resembles an eagle.
“Ice in Boiling Water”
The researcher has been looking for binary star systems, in which the larger star produces very bright explosions called “bursts.”
However, the data showed that this explosion was surrounded by cold gas, suggesting it was not a binary star system. And NASA’s NEOWISE infrared space telescope showed that months before the explosion, dust had begun to clear the area.
Even more intriguing was the fact that the explosion produced about 1,000 times less energy than previously observed mergers between stars.
“We asked ourselves: What is 1,000 times less massive than a star?” said De. The answer was close to Earth: Jupiter.
The team of researchers from MIT, Harvard and Caltech determined that the engulfed planet was a gas giant with a mass similar to Jupiter, but it was so close to its star that it orbited the star in just one day.
The star, which is very similar to the sun, engulfed the planet over a period of about 100 days, beginning to “nibble” its edges, ejecting dust.
The bright explosion happened in the past 10 days, when the planet was completely destroyed as it crashed into the star’s interior.
Miguel Montarges, an astronomer at the Paris Observatory who was not involved in the study, noted that the star was thousands of degrees hotter than the planet.
“It’s like putting an ice cube in a pot,” he told AFP.
To see the fate of the earth
Morgan MacLeod, a postdoctoral fellow at Harvard University and co-author of the study, published in the journal Nature, said most of the thousands of planets discovered so far outside the solar system “will eventually meet this fate.”
When the sun expands beyond Mercury, Venus and Earth in about five billion years, these planets will have “less dramatic perturbations” because rocky planets are much smaller than gas giants, MacLeod explained.
“In fact, it will be very small disturbances in the solar energy production,” he stressed.
But even before it is “swallowed up,” Earth will already be “quite inhospitable,” because the sun has evaporated all of the planet’s water, MacLeod added.
Ryan Lau, an astronomer and co-author of the study, believes the discovery “speaks to the transience of our existence.”
“After the billions of years of our solar system’s lifespan, our own final phase will likely end in a final outburst lasting only a few months,” he said in a statement.
Now that astronomers know what to look for, they hope to see many more planets consumed by their stars soon.
In the Milky Way alone, this phenomenon may occur once a year, De said.
Source: DN
