Astronomers discover strange white dwarf with hydrogen on one side and helium on the other – News – Radio Central Rti
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Time: 2023-07-20 20:26 News Citation: Central News Agency Contributing Editor: News Editor Astronomers have discovered a strange double-sided star, a white dwarf that appears to be composed almost entirely of hydrogen on one side and helium on the other. (Picture: caltech.edu)
Astronomers have discovered a double-faced star, a white dwarf that appears to be made almost entirely of hydrogen on one side and helium on the other, puzzling astronomers, reports The Guardian.
“The two sides of the surface of this white dwarf have very different changes,” said astrophysicist Ilaria Caiazzo of the California Institute of Technology (Caltech). “When I showed the observations to people, they were amazed.” This is the first time astronomers have spotted a lone star in the sky with two sides in stark contrast.
The two-faced star, nicknamed Janus after the Roman symbol of transformation, is located more than 1,000 light-years away in the constellation Cygnus, according to the findings published in the journal Nature. Double-faced god, the official scientific name is ZTF J203349.8+322901.1.
The white dwarf was first discovered by the Zwicky Transient Facility. The Zwicky Transient Probe is an instrument that scans the sky every night from Caltech’s Palomar Observatory near San Diego.
As Caiazzo searched for white dwarfs, one candidate stood out because of its rapid change in brightness. Further observations by the researchers found that Janus rotates around its own axis every 15 minutes. Spectroscopic measurements that determined the star’s chemical footprint revealed that the object was composed almost entirely of hydrogen on one side and helium on the other.
If you look closely, you can see that both sides of the star are bluish and of the same brightness, but the side that is almost all helium, like the sun, looks grainy and patchwork, and is almost entirely made of helium. The hydrogen side looks smoother and smoother.
The star’s exterior is composed of swirling gas, making it difficult to explain its two-sided nature. One theory is that Janus may be undergoing a rare transformation that has been predicted to occur during the evolution of white dwarfs.
White dwarfs are the remnants of red giant stars after they have exhausted their fuel. As they age, stars expand to become red giants. Eventually, the loose outer matter is blown away, and the core shrinks into a dense, hot, high-temperature white dwarf about the mass of our sun but about the size of Earth.
The star’s intense gravitational field causes heavier elements to sink toward the core and lighter elements to float up, creating two atmospheres, with helium at the bottom and a thin layer of hydrogen above.
“There are only some white dwarfs whose surfaces transition from being mostly hydrogen to being mostly helium,” Caiazzo said. “We may have caught a white dwarf that is going through this transition.”
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