The Astronomers Discover an Unusual Cosmic Pair Through Mysterious Radio Signals
Astronomers believe they’ve identified the source of the signal, but this discovery brought with it a new mystery–one that they now claim to have solved as well. The Curtin node, part of the International Centre for Radio Astronomy Research’s (ICRAR), first discovered the radio signal when they were looking through the archived data of the Murchison Widefield array (MWA), an Australian radio telescope. The energy pulse is the longest-period radio transient ever detected, with most signals appearing on timescales between tens to thousands of seconds.
Long-period radio transients are relatively new, with several having been discovered recently. Radio waves can be produced by celestial objects that have a magnetic field in flux, such as the Sun and Jupiter. The radio transients on shorter timescales are sudden, short-lived bursts that emit energetic emissions. They are usually produced by rotating neutron star (the collapsed core a dead-star). When you look at them, however, it looks like 2001: A Space Odyssey. ‘My god, it’s full of stars!’.”
Luckily, the newly discovered radio transient, GLEAM-X J0704-37, was not hiding behind stars. It was found on the outer edge of the Milky Way, around 5,000 light years away, in the constellation Puppis. This region is less crowded than the rest. The team that made the discovery was able to identify the star using the MeerKAT telescope located in South Africa. Using another telescope, the SOAR observatory in Chile, the researchers then measured the star’s spectrum, determining that it is an M dwarf star, also known as a red dwarf star.
Although the team solved one mystery by locating the source of the signal, another mystery now lay ahead. Hurley-Walker stated that an M dwarf could not produce the energy seen. The M dwarfs have low mass stars with a fraction of the Sun’s luminosity and mass. They constitute 70 per cent of the stars in the Milky Way, but not one of them is visible to the naked eye.”
Instead, the data suggested that the M dwarf was in cahoots with another type of star, both working together to produce the repeating radio transient. The M dwarf may be in a binary with a white dwarf, which is the remnant of a star after it has lost its outer layers and exhausted its nuclear fuel. “Together, they power radio emission,” Hurley-Walker said.
Although the archival data of MWA showed that the radio transient has been active for 10 years, it may have been emitting bursts of energy for even longer that had gone undiscovered. The team behind this discovery wants to do follow-up observations on GLEAM X J0704 37, and dig through the data in order to find other long-period transients. It’s possible that there are many more strange cosmic sources pulsing energy throughout the universe.
