Astronomers watching the Southern Constellation of Ara from the MeerKAT telescope in the Karoo desert of South Africa detected a mysterious and puzzling radio signal that may reveal an entirely new type of star system. Or something else. Radio telescopes don't show a zoomed-in version of what we would see with the naked eye, but a picture of the invisible radio emissions. It ends up looking like a bunch of white blobs accompanied by a string of data for astronomers to interpret. There's a lot of room for error.
The astronomers at MeerKAT watched as an object brightened in its radio emissions over the course of three weeks by a factor of three. This was MeerKAT's first discovery of a so-called "transient source," an object that varies in brightness over a period of time. Once again proving there's no one better at naming things than scientists, the object was given the name "MKT J170456.2-482100." Further observations of the object from other telescopes revealed it to be a binary star system—a system where two stars orbit each other.
That's not all that strange. Binary star systems are well understood by astronomers. But what makes this system bizarre is that it doesn't fit into any of the known types of binary star systems.
One of the stars has already been well documented by astronomers for the last 18 years. TYC 8332-2529-1 is about 1,800 light-years away from Earth. Observations from the SALT telescope shows that this star has a magnetic field and orbits a much fainter, mysterious companion star every 21 days. It's this mysterious companion that has researchers puzzled.
Many binary star systems have a white dwarf as one of their halves. Yet the mysterious companion star is much larger than most white dwarfs, roughly 1.5 times the mass of our Sun.
The strange radio flares could be explained by a giant star orbiting closely with a sun-like star. However, spectral analysis of the strange companion star offers no evidence that it is in fact a sun-like star.
So what is it? No one knows yet. Ben Stapper, one of the researchers working on figuring out what's going on here, suggests that this may be evidence of an entirely new type of binary star system. It may be composed of a giant star orbiting a neutron star. Or it could be that the giant star is orbiting a black hole.
MeerKAT is going to continue monitoring the mysterious radio source every four weeks for the foreseeable future. Scientists hope that continued monitoring of this star system will shed some light on this strange and possibly never-before-seen star system. Findings like these offer even more proof that the cosmos is much bigger and stranger than we can imagine.