Astronomers Found a 'Dead Star' 1,600 Light-Years Away From Earth Sending out Mysterious Signals Every Two Hours

Astronomers are continuously in the pursuit of solving multiple space mysteries. One of these discoveries recently found an answer, stated SciTech Daily. Data from multiple telescopes was analyzed to resolve this decade-long question. Findings regarding this mystery were published in the journal Nature Astronomy.

The enigma in question was a radio mystery first identified in 2015. Researchers observed radio pulses generating from space every two hours but could not locate their origins. Initially, experts thought that the pulses came from neutron stars. However, a team of international astronomers has proved this assertion to be wrong and has analyzed the source to be a binary star system containing a dead star.

The duration of the pulses ranges from seconds to minutes in length. The most noteworthy aspect of these pulses is that they routinely happen every two hours. Astronomers in recent years have found many fast radio bursts (FRBs), but such subtle bursts remain rare. "The radio pulses are very similar to FRBs, but they each have different lengths," said Northwestern astrophysicist and study coauthor, Charles Kilpatrick. "The pulses have much lower energies than FRBs and usually last for several seconds, as opposed to FRBs, which last milliseconds. There’s still a major question of whether there’s a continuum of objects between long-period radio transients and FRBs, or if they are distinct populations."

This system comprises a red dwarf and a white dwarf star which are orbiting each other somewhere around the Big Dipper. The duo are so close in distance that their magnetic fields are clashing. The two stars pulsing together eventually produce a powerful radio burst. The binary system is located just 1,600 light-years from Earth. Researchers further observed that both stars are orbiting the same center of gravity and make a revolution every 125.5 minutes.

For the study, the team garnered data from multiple telescopes situated at the MMT Observatory in Arizona and the McDonald Observatory in Texas. The team observed the binary system during its two-hour cycle of pulsing. Their objective was to understand the variations in the system. The experts garnered the optical spectra from the red dwarf star. This implies that they split the emitted light from the red dwarf star into its component colors to gain more information about the celestial body. "The spectroscopic lines in these data allowed us to determine that the red dwarf is moving back and forth very rapidly with exactly the same two-hour period as the radio pulses," Kilpatrick said. "That is convincing evidence that the red dwarf is in a binary system."

Researchers concluded that the back-and-forth motion was due to the gravitational pull of a companion star. The variations in the motion implied that the companion star's mass aligned with that of a white dwarf star. "In almost every scenario, its mass and the fact that it is too faint to see means it must be a white dwarf," Kilpatrick said. "This confirms the leading hypothesis for the white dwarf binary origin and is the first direct evidence we have for the progenitor systems of long-period radio transients." The system was labelled ILT J1101 + 5521 by the officials.

This is the first time researchers have found proof of binary stars producing such pulses. "There are several highly magnetized neutron stars, or magnetars, that are known to exhibit radio pulses with a period of a few seconds," said Kilpatrick. "Some astrophysicists also have argued that sources might emit pulses at regular time intervals because they are spinning, so we only see the radio emission when the source is rotated toward us. Now, we know at least some long-period radio transients come from binaries. We hope this motivates radio astronomers to localize new classes of sources that might arise from neutron star or magnetar binaries."