A white dwarf star has caught the attention of astronomers, not only because of the intrigue surrounding these tightly wound stars, but also because it appears to have two faces. The two-faced white dwarf is known as Janus, a nod to the Roman god of duality and transition. More officially Janus is known as ZTF J203349.8+322901.1, and it was discovered using the Zqicky Transient Facility (ZTF).
While ZTF might have made the initial discovery, the big, intriguing discovery surrounding this star was made later, with the W.M. Keck Observatory in Hawaii, which revealed that the star has a very unusual spectrum – one side is made up of helium, while the other is a hydrogen-dominant surface.
This is the first time that we’ve discovered a star with two different types of surface compositions, too, and the researchers believe we could be looking at a star that is in the process of transitioning from one type of surface to another, creating this weird effect.
The researchers behind the discovery include Ilaria Caiazzo and several others working with Caltech. Understanding the reasoning behind the strange star’s double composition would help us better understand these tightly packed cosmic objects, too. Something that has been a goal for astronomers since the first white dwarf was discovered several years ago.
Another belief is that the magnetic fields on the star could be causing the separation. It could be changing the pressure of the planet. The next step, though, is to find more two-faced white dwarf stars like this, and to study them more in-depth to see if the same occurrences are happening there, to hopefully pinpoint exactly why the star is composed the way it is.
In the meantime, at least, we have plenty of other astronomical observations to follow, including the latest discoveries by the James Webb space telescope, which are completely changing what we thought we knew about our universe’s evolution.