Although the sun is alone in the universe, more than half of the stars in the Milky Way are paired with other stars in binary systems, orbiting each other so tightly that it’s easy to spot one cannibalizing the other. Recently, astronomers discovered the shortest orbits of binary stars ever detected, taking only 51 minutes to circle each other, and one of the white dwarf stars is violently peeling away the outer material of the companion star like an onion.
When the MIT team combed through a database of more than 1 billion stars, they discovered a new binary system close to each other at a distance of about 3,000 light-years from the sun, called ZTF J1813+4251, with a sun-like mass similar to Jupiter. stars, and a white dwarf.
Binary star systems are not uncommon, and more than 50 percent of the stars in the Milky Way are systems of two or more stars that share a center of gravity and compete for fuel with each other. But astronomers rarely find binary systems with orbital periods shorter than an hour—especially including large Sun-like stars, which typically take hours to orbit each other.
However, ZTF J1813+4251 belongs to the Cataclysmic variable star (CV) system, and the orbits of each other are extremely compact, so that the huge gravitational force of the white dwarf has an extremely strong and tyrannical control over the companion star, which is like peeling an onion. Sucks away hydrogen, triggering a huge flare that looks like a supernova explosion.
Once the starving white dwarf has stripped the hydrogen of the companion star’s atmosphere, it will begin to devour helium from the companion star’s exposed core, but since helium is heavier than hydrogen, the Sun-like star should have enough mass to maintain a super-compact orbit with the white dwarf. , in about 70 million years, the two stars will get closer and closer, and the orbital period of each other may gradually shorten to only 18 minutes.
But the loss of mass will cause the Sun-like star to expand, so the two stars will split again for the last few hundred million years, when the orbital period remains at about 30 minutes until the Sun-like star burns out.
The new paper is published in the journal Nature.
(First image credit: MIT/Harvard-Smithsonian Center for Astrophysics)
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