Being labelled as “two-faced” is usually an insult, but in the case of a newly-discovered star, the label is being hailed as exciting.
A group of astronomers, including a UBC alumna and a UBC astronomer, say for the first time they’ve found a star with two “faces,” one side composed completely of helium and the other completely of hydrogen.
The discovery was published in the journal Nature on Wednesday.
The star body in question, dubbed Janus after the two-faced Roman god of transition, is a white dwarf, an ultra-dense stellar body that is the remains of a star once like our own sun.
“The surface of the white dwarf completely changes from one side to the other,” first author Dr. Ilaria Caiazzo, a post-doctoral scholar at the California Institute of Technology and UBC alumna, said in a media release .
“When I show the observations to people, they are blown away.”
Astronomers say helium and hydrogen are both common components of white dwarfs.
But the complete division of the elements on separate sides of the star is a new finding, according to co-author and UBC physics and astronomy professor Dr. Jeremy Heyl.
“Imagine if you were looking at the earth, it would be like seeing only the ocean. Then it turns, and there would be only land,” he said.
According to the team’s study, Janus spins on its axis every 15 minutes.
The researchers were able to use spectrometry — the measurement of the interaction of light and matter — to inspect wavelengths from the star for chemical fingerprints.
