According to a new study published Thursday in Nature, “very special” stars are heavier than our Sun and are all crammed into a relatively small body the same size as our Moon. .. It was formed when two not-so-tall white dwarfs, who spent their life as a couple orbiting each other, collided and merged.
At the end of their life, most stars become white dwarfs. And, aside from being essentially a smoking corpse, it’s one of the densest objects in the universe... In about 5 billion years, our Sun will eventually become a red giant before suffering the same fate.
“It might sound counterintuitive, but the little white dwarf is heavier,” lead author Ilaria Caiazzo said in a statement. “This is because white dwarfs lack nuclear fusion, which holds normal stars against their own gravity, and instead their size is regulated by quantum mechanics. “
A highly magnetized dead star named ZTF J1901 + 1458 is relatively close to Earth, just 130 million light years away. It was discovered by the Zwicky Transient Facility (ZTF) at the Palomar Observatory of the California Institute of Technology.
When the two white dwarfs merged, they combined to form a new star. It weighs about 1.35 times the mass of our Sun and is the heaviest we have ever found. If either star had a slightly greater mass, the merger would have caused the following violent explosion:..
The ZTF J1901 + 1458 also has an “extreme” magnetic field which is about a billion times stronger than the Sun, spinning quickly and revolving in just seven minutes. It takes about 27 days for the sun to turn.
With a diameter of 2,670 miles, she is known as the smallest white dwarf in the universe, over 400 miles. By comparison, the diameter of the moon is 2,174 miles.
“I grabbed this very interesting object which was not big enough to explode,” said Caiazzo. “We’re really studying how huge a white dwarf can be. “
So what’s next to the rare star?
Researchers believe that stars are likely of sufficient mass to evolve.This is usually formed when a star with a mass much greater than the Sun explodes in a supernova. If their hypothesis is correct, it means that many neutron stars in the universe may have been formed in this previously unknown manner.
“It’s so heavy and dense that in its nucleus, electrons are captured by protons in the nucleus to form neutrons,” Caiazzo said. “The pressure of the electrons opposes gravity, leaving the star intact, so the nucleus collapses when enough electrons are withdrawn. “
The fact that the stars are close to Earth and young (only around 100 million years old or less) means that similar stellar phenomena can occur more frequently in our own galaxies.
“Until now, we have not been able to systematically explore short-scale astronomical phenomena at this type of scale. The results of these efforts are incredible, ”said the first star found in sky images. said Kevin Barge.
But researchers say they’re just getting started.
“There are a lot of questions to be addressed, like the rate of fusion of white dwarfs in the galaxy. Is this sufficient to explain the number of type Ia supernovae? said Caiazzo. “How are magnetic fields generated by these powerful events, and why are there such variations in the strength of the magnetic field in white dwarfs? The greatness of white dwarfs born of fusion. Finding a group will help you answer all of these questions and more. ”
Source link Astronomers discover record stars as small as the Moon but heavier than the Sun