In their search for highly magnetized white dwarfs, astronomers at Caltech detected an object that changes dramatically in brightness every 15 minutes using the Zwicky Transient Facility (ZTF) instrument at Palomar Observatory near San Diego. Scientists working under Ilaria Kayazu, I decided to take a closer look at it.
During the observations, it turned out that this white dwarf actually makes a complete revolution on its axis every 15 minutes. But the most interesting thing is that the changes in its brightness are caused by the fact that its two halves are very different in chemical composition: half of the white dwarf is made of hydrogen, and the other half is made of helium. This chemical chameleon was named by scientists Janus, after the two-faced Roman god.
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Spectroscopic observations made at the WM Keck Observatory atop the extinct Maunakea volcano in Hawaii allowed us to get a closer look at the nature of this unusual object. It turns out that on the one hand, Janus, the spectrum of hydrogen can be seen without any trace of helium, and on the other hand, only the spectrum of helium.
how did that happen?
This discovery surprised scientists, but over time, several theories emerged that could explain the unusual two-faced white dwarf. It is possible that the researchers were simply able to notice a rare stage in the evolution of white dwarfs. It has long been known that some bodies of this type undergo metamorphism, in which the surface changes from hydrogen to helium. So it is possible that Janus is in the midst of such a transformation.
However, the question arises as to why this change does not occur gradually over the entire surface, but rather at a local level. This question has not yet been answered, although researchers suspect that magnetic fields may be behind this unusual process. The magnetic fields of celestial bodies are often asymmetric. On the one hand, the stars may be more powerful than on the other. This, in turn, leads to a situation where on the one hand the star operations of the blending elements are hindered, and on the other hand they are facilitated. It is also possible that the magnetic field affects the pressure and density of the gases surrounding the white dwarf. In such a situation, it would theoretically be possible to create a kind of hydrogen ocean on the side of the star where the magnetic field is stronger.
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Janus keeps many secrets from scientists so far, but researchers are convinced that further observations made with ZTF, a. Also in the future at the Vera C. Rubin Observatory in Chile, it will help us find more objects of this kind, and thus bring us closer to solving their mystery.
Echo Richards embodies a personality that is a delightful contradiction: a humble musicaholic who never brags about her expansive knowledge of both classic and contemporary tunes. Infuriatingly modest, one would never know from a mere conversation how deeply entrenched she is in the world of music. This passion seamlessly translates into her problem-solving skills, with Echo often drawing inspiration from melodies and rhythms. A voracious reader, she dives deep into literature, using stories to influence her own hardcore writing. Her spirited advocacy for alcohol isn’t about mere indulgence, but about celebrating life’s poignant moments.
